Distributed edge switching system for voice-over-packet multiservice network

ABSTRACT

A network device including a plurality of communication interfaces, including a telephone line interface, a computer data interface, and a broadband network interface; a processor; a machine-readable storage medium which during use stores a call processing application and service profiles, and which stores executable instructions to mediate communications between the plurality of communication interfaces, the instructions causing the network device to detect network signaling events or trigger points in a telephone call and invoke the call processing application in response to the detected network signaling events or trigger points, the call processing application operating according to parameters defined in the service profiles.

RELATED APPLICATION

[0001] This application claims priority to U.S. provisional application60/283,888 filed on Apr. 13, 2001, the contents of which areincorporated herein by reference.

TECHNICAL FIELD

[0002] This invention relates to packet networks, and more particularlyto network devices.

BACKGROUND

[0003] This section contains a discussion of background. It summarizestelecommunications carrier network architectures that currently exist aslegacy or that are currently under development. It also includesdiscussion of insights and observations made by the inventor about theprior art systems that are helpful to understanding the subsequentlydescribed invention but that were not necessarily appreciated by personsskilled in the art or disclosed in the prior art. Thus, the inclusion ofthese insights and observations in this background section should not beinterpreted as an indication that such insights and observations werepart of the prior art. After the background discussion, a new EdgeSwitched Network (ESN) architecture is introduced and it is describedand compared to leading “Next Generation Network” alternatives. ADistributed Edge Switch (DES) makes possible the implementation of anESN. In the OVERVIEW section that is found in the Detailed Descriptionsection, the design, operation and management of the DES are describedwithin the architectural context provided by the ESN.

Next Generation Networking Approaches

[0004] In recent years, attempts to transform the legacy Public SwitchedTelephone Network (PSTN) to exploit the potential of the Internet hasled to approaches that are loosely referred to as the Next GenerationNetwork (NGN). It was believed that such approaches would lead toconverged networks. Converged networks promise substantial cost savingsand new service opportunities for telecommunications carriers (a.k.a.“carriers,” or “network service providers”). As a means to realize newdata services, carriers have deployed overlay networks, which requireoverlay of new infrastructure onto existing legacy voice networks. Incontrast, the converged approach of the NGN seeks to eliminate the needto have separate networks for different media. It exploits theprinciples of “openness” and leverages the standard protocols of IPnetworks to carry not only data but also other media such as voice andvideo.

The PSTN and AIN Principles

[0005] The NGN grew out of the PSTN, thus to understand its origins onemust understand present day Advanced Intelligent Network (AIN) employedby PSTN carriers to provide advanced telephony services. The AIN wasproposed as the solution to the carriers' needs to produce applicationsrapidly and independently of switch development efforts. Priorapproaches had bundled services within switches, giving rise to longdevelopment times and inflexible service deployment. Service developmentand deployment was intimately tied to switch evolution and switchdevelopment cycles.

[0006] AIN proposed de-coupling service development and service logicfrom switches by building appropriate trigger points within the switch.Upon encountering a trigger detection point while processing a call, theswitch, called the Service Switching Point (SSP), would trigger and senda query to a Service Control Point (SCP). FIG. 1 illustrates theelements of AIN. The SSP performs a query directed to an SCP. The SCPexecutes service logic that yields a result and that result is returnedto the SSP that initiated the query. The SSP then continues with callprocessing.

[0007] As an example, when a subscriber dials an 800 number, an SSPdetects that the call requires AIN service logic processing. The SSPdirects a query to an SCP which in turn executes service logic thatreturns a valid dialing number to the SSP. The SSP then asks theSignaling System #7 (SS#7) network to set-up a call to that telephonenumber. SS#7 sets up signaling and bearer paths necessary to support acall to that dialing number. The CENTRAL OFFICE SWITCH serving thecalled party applies a ringing tone to the called party's telephone.Once the called party answers, the call is established and both theparties can now have a telephone conversation.

[0008]FIG. 1 depicts the structure of the PSTN, including its supportfor AIN. The CENTRAL OFFICE SWITCH is decomposed into four distinctmodules:

[0009] CALL PROCESSING

[0010] LINE

[0011] SIGNALING

[0012] TRUNK

[0013] The LINE module functions include detecting on-hook/off-hook,applying dial tone and ringing tone, collecting dialed digits, andcommunicating internally with the call-processing module. The CALLPROCESSING module analyzes the digits collected by the LINE module, andasks the SIGNALING module to perform appropriate actions. The SIGNALINGmodule interfaces with the SS#7 TRANSPORT NETWORK for the purpose ofsetting up a bearer channel between the calling and the called CENTRALOFFICE SWITCHES. The TRUNK module transforms analog voice to a TimeDivision Multiplexed (TDM) format for transmission over PSTN trunks. TheTRUNK module of the CENTRAL OFFICE SWITCH serving the called partyconverts the TDM trunk format back to analog for transmission over thelocal loop.

The Next Generation Networking Model

[0014]FIG. 2 illustrates the NGN approach. The NGN exhibits severalsimilarities to the legacy PSTN. If one were to split apart the fourmodules that comprise the CENTRAL OFFICE SWITCH (see FIG. 1) intoseparate and distinct computing elements, the following components of aNGN network result:

[0015] MEDIA GATEWAY CONTROLLER

[0016] RESIDENTIAL GATEWAY

[0017] TRUNK GATEWAY

[0018] SIGNALING GATEWAY

[0019] To compare the functions of these elements to analogous functionsin the CENTRAL OFFICE SWITCH, the MEDIA GATEWAY CONTROLLER (A.K.A.“softswitch,” or “call agent) performs the functions of the CALLPROCESSING module, the RESIDENTIAL GATEWAY (A.K.A. “customer gateway”)performs the functions of the LINE module and the TRUNK GATEWAY replacesthe TRUNK module. Insofar as the RESIDENTIAL GATEWAY and TRUNK GATEWAYare both responsible for converting media provided in one type ofnetwork to the format required in another type of network, they arereferred to generically as MEDIA GATEWAYS. With respect to support fornetwork signaling functions, the SIGNALING GATEWAY in the NGN replacesthe SIGNALING module in the CENTRAL OFFICE SWITCH. The similaritiesbetween the PSTN and NGN end here.

[0020]FIG. 2 shows a PACKET TRANSPORT NETWORK based on IP in OSI Layer 3(the network layer) transported over ATM in OSI Layer 2 (the datalinklayer). It interconnects all four NGN network elements. What were oncemajor modules within a CENTRAL OFFICE SWITCH are now distributed networkelements interconnected through a PACKET TRANSPORT NETWORK. Thedistributed nature of network elements in an NGN brings out one of themost striking differences between the PSTN and the NGN approaches. Thetheoretical advantages to be gained from this distribution include thefollowing:

[0021] The MEDIA GATEWAY CONTROLLER may be implemented on a reliable,high-performance, fault-tolerant server that is IP-based and usesstandard protocols to communicate with the gateways. Services can beimplemented on separate platforms using open application programminginterfaces (API), which should in theory lead to rapid development anddeployment of services.

[0022] The MEDIA GATEWAYS can send media to each other over an IP-basedPACKET TRANSPORT NETWORK using a protocol called Real Time TransportProtocol (RTP). The RTP protocol can be used to transmit not only voicebut also data and video. The same IP transport and protocol can be usedto carry multiple media types concurrently, a task that is difficult toaccomplish with the circuit-switched PSTN network.

[0023] Unlike with the PSTN, where the signaling network is separatefrom the voice network, NGN utilizes the same PACKET TRANSPORT NETWORKto carry both signaling and media traffic.

[0024] Whereas communication between the four major modules is internalto the CENTRAL OFFICE SWITCH in the PSTN, the NGN uses a gateway controlprotocol for communication between the MEDIA GATEWAY CONTROLLER and theMEDIA GATEWAYS.

[0025] The most widely studied gateway control protocol is Media GatewayControl Protocol (MGCP) described by IETF RFC 3015 on Megaco ProtocolVersion 1.0. RFC 3015 is a common text with ITU-T Recommendation H.248,the most recent draft of which was developed as a close cooperationbetween the IETF Media Gateway Control Working Group (A.K.A. “MEGACOWorking Group”) and ITU-T Study Group 16.

[0026] The precursor to MGCP was the Simple Gateway Control Protocol(SGCP) developed by Telcordia. At about the same time Telcordia wasimplementing SGCP, a company called Level 3 had developed a similarprotocol called IP Device Control (IPDC). Rather than have two similarprotocols develop and compete over time, Telcordia and Level 3 mergedthem into MGCP. MGCP was tailored to address a PSTN telephone and wasnot designed to handle data or multimedia. ITU-T Study Group 16 extendedMGCP to support ISDN and multimedia, which led to Recommendation H.248.This body of work is today referred using the moniker MEGACO/H.248; itdetails a NGN reference architecture that provides an operationalcontext for the description of the MGCP itself.

[0027]FIG. 2 depicts an NGN that is architecturally compatible withMEGACO/H.248. The following workflow sequence illustrates a typical callset-up procedure for the NGN depicted in FIG. 2:

[0028] (1) A telephone goes off-hook. The RESIDENTIAL GATEWAY servingthe telephone detects the off-hook event, applies dial tone, collectsthe dialed digits, and notifies the MEDIA GATEWAY CONTROLLER usingMEGACO; The RESIDENTIAL GATEWAY also informs the MEDIA GATEWAYCONTROLLER that it is prepared to receive an RTP media stream at acertain port address, and further indicates the audio coding format itis able to support.

[0029] (2) The MEDIA GATEWAY CONTROLLER processes the digits and thenmust determine whether the called party telephone is connected toanother RESIDENTIAL GATEWAY within the NGN or connected to a CENTRALOFFICE SWITCH in the PSTN.

[0030] (3) Assuming the called party is connected to another RESIDENTIALGATEWAY within the NGN, the MEDIA GATEWAY CONTROLLER queries theRESIDENTIAL GATEWAY serving the called party for an RTP port (and theaudio coding format) at which it would prefer to receive an RTP streamfrom the calling party RESIDENTIAL GATEWAY.

[0031] (4) The called party RESIDENTIAL GATEWAY responds with the portat which it can receive an RTP audio stream from the calling party andthe audio coding format it is able to support.

[0032] (5) The called party RESIDENTIAL GATEWAY applies a ringing toneto the called party's telephone.

[0033] (6) The MEDIA GATEWAY CONTROLLER informs the calling RESIDENTIALGATEWAY of the audio coding format supported by the called RESIDENTIALGATEWAY and the port at which it is expecting to receive an RTP stream.

[0034] (7) Following more exchanges of information, both the calling andcalled party RESIDENTIAL GATEWAYS know the port addresses and supportedaudio coding formats necessary for them to send and receive RTP streams(containing encoded audio) to/from each other.

[0035] (8) Once the called party answers the telephone, two-waycommunication using RTP streams is established.

Implications of NGN Deployment

[0036] There are several significant implications that result fromdelivering network services to subscribers through an NGN rather thanthe PSTN. Several of them are summarized in the points below:

[0037] Unlike the PSTN, which has a signaling network that is separatefrom the TDM network for establishing bearer paths, the NGN networkcarries both signaling and media streams over the same IP network,thereby achieving a certain measure of convergence.

[0038] Whereas the PSTN requires separate overlay networks and protocolsfor other media beyond voice, the NGN utilizes the same IP network andprotocols for all media communications (i.e. voice, data, video).

[0039] While the PSTN carries voice media over dedicated circuitswitched connections, NGN carries media streams in RTP packets that aretreated in the same manner as any other IP packets, using the “besteffort” paradigm the Internet employs for routing packets. This meansthat packets can encounter delays; they can be dropped due to congestioncontrol mechanisms that throttle packets at the source or at the ingressto the network. Hence, the bare public Internet does not offer qualityof service. Consequently, an NGN implementation requires the creation ofa special-purpose IP network to support network quality of service(QoS). In contrast, the PSTN is capable of guaranteeing QoS service forpoint-to-point connections transporting voice or data.

[0040] The NGN interworks with the PSTN via TRUNK GATEWAYS and SIGNALINGGATEWAYS. Thus, while the end-to-end connection between two NGNsubscribers would occur entirely within the PACKET TRANSPORT NETWORK,the end-to-end connection between and NGN subscriber and a PSTNsubscriber would occur in both the NGN and the PSTN, using a TRUNKGATEWAY and a SIGNALING GATEWAY to carry bearer channel content andnetwork signaling information, respectively, between the two subscribersparticipating in the call.

[0041] Third-party applications can be offered via an open applicationsprogramming interface (API) offered by the MEDIA GATEWAY CONTROLLER.Some standards for Open APIs include PARLAY, JAIN, XML, or SOAP. It isbeyond the scope of this discussion to provide definitions for theseAPIs or to elaborate on them beyond presenting their monikers. Let itsimply be said that the thrust of these APIs was originally an effort tomake AIN infrastructure in the PSTN accessible to third-partyapplication providers so that they could offer new and innovativenetwork services. With the advent of the NGN, it was envisioned that thesame set of APIs would be suitable to provide third-party NGNapplications with the ability to access similar features by interfacingwith the MEDIA GATEWAY CONTROLLER.

[0042] The NGN makes it possible for a carrier to provide plain oldtelephone service (POTS) over a PACKET TRANSPORT NETWORK by using aMEDIA GATEWAY CONTROLLER and a RESIDENTIAL GATEWAY rather than a CENTRALOFFICE SWITCH. As already explained, the RESIDENTIAL GATEWAY takes onthe role of the LINE module of the CENTRAL OFFICE SWITCH; therefore,there are no NGN requirements to change the telephone itself.

A Victim of Failed Economics

[0043] Though the NGN is today restricted in its applicability to voicecommunications, it was originally the hope of both carriers and vendorsthat voice-over-IP (VoIP) would serve to bootstrap the NGN and spawn offa new era of converged networks that would cater to voice, video anddata communications. Convergence promised to transform the PSTN into ageneral purpose “multi-service network” capable of simultaneouslydelivering voice, video and data services through a common PACKETTRANSPORT NETWORK that supports QoS. Thus far this expectation has notmaterialized due to the carriers' reluctance to widely deploy a networkbased on the NGN architecture. At the current time, many carriersperceive the NGN architecture unsuitable to meet their forward-lookingobjectives to decrease network operating costs while at the same timeincrease network service revenues. Ultimately the NGN became a victim offailed economics that resulted from its inordinate complexity andinsufficient support for new services.

Complexity Confounds NGN Deployment

[0044] The inordinate complexity of the NGN is to a large extent due tooverreliance on centralized control elements for network servicedelivery. While its many network elements may be physically distributed,the NGN architecture's logical centralization mimics the functionally ofthe “mainframe-oriented” PSTN. The NGN architecture has more recentlybeen altered from its original design to model the Internet, relyingupon a “horizontal integration” of specialized, cooperating networkelements. Many of these network elements are not shown in FIG. 2, butare necessary for NGN implementation (e.g. feature servers, mediaservers, integrated access device controllers, policy servers, domainnaming servers, SIP proxy servers, TRIP servers, subscriber directoryservers). Very much unlike the internet, virtually all NGN networkelements require some degree of centralized control by, or interactionwith, the MEDIA GATEWAY CONTROLLER according to specialized protocols.All of these protocols communicate through (i.e. generate traffic on)the carrier's PACKET TRANSPORT NETWORK.

[0045] To support its centralized service delivery model, the“vertically integrated” PSTN was based on a hardware scaling model inwhich the majority of software processes communicated directly with eachother inside purpose-built hardware computing modules. These computingmodules physically plugged into each other to create large, distributedmainframe computers such as the CENTRAL OFFICE SWITCH. The morehorizontally integrated NGN is based on a software scaling model thatfor all intents and purposes remains as operationally centralized as thePSTN, if not more so in some instances where control over a very largenumber of subscribers (potentially millions) may be aggregated into aregional office. Adherents of the NGN architecture maintain that such ahigh degree of centralization offers cost benefits; however the costbenefits of centralization are to a large measure offset by faultvulnerability and the costs associated with ensuring system redundancy.Generally speaking, if something in a network does anything forthousands of subscribers at the same time, not only does the carrierneed two of them, but also the ability to automatically fail over fromone to the other without dramatically interrupting service delivery.Implementing this level of functionality for centralized components ischallenging and often prohibitively expensive.

[0046] As depicted in FIG. 2, the physically distributed,highly-decomposed NGN architecture relies upon a an “orchestra”0 ofinterdependent software services running on distributed networkelements; these software services, each according to its unique role,communicate in one-to-one, many-to-one, or one-to-many relationshipswith other interdependent software services through the PACKET TRANSPORTNETWORK, each using specialized protocols.

[0047] Due to physical limitations on how many MEDIA GATEWAYS can becontrolled by a single MEDIA GATEWAY CONTROLLER, the NGN must bepartitioned into control zones. Local device-level signaling performedby the MEDIA GATEWAY CONTROLLER within its control zone must be somehowsynchronized with end-to-end network signaling that would be necessaryfor a call to span more than a single zone. The result is a two-tieredsignaling architecture—a concession to the inelegant NGN scaling modeland its inherent requirement for network partitioning. Network signalingprotocols such as Session Initiation Protocol (SIP) are used betweencontrol zones for end-to-end network signaling, whereas MEGACO is usedcloser to the endpoint for local MEDIA GATEWAY control.

[0048] Among other things, the two-tiered signaling model complicatesthe integration of APPLICATION SERVERS (and potentially PBXs) thattypically require more signaling information than can be conveyed byMEGACO (e.g. calling and called party dialing numbers). As a result,network signaling using SIP must be extended directly to the APPLICATIONSERVER as if it were another MEDIA GATEWAY CONTROLLER i.e. another“control zone.” Thus, for the NGN to enable network-based enhancedservices such as voice mail or group conferencing, it must interfaceAPPLICATION SERVERS using a different method than the way it interfacestelephones. From an operational perspective, the two-tiered signalingmodel means that the MEDIA GATEWAY CONTROLLER becomes a lynch pin, andmust now actively mediate all telephone access to the APPLICATIONSERVERS.

[0049] In the NGN, subscriber telephones are connected throughRESIDENTIAL GATEWAYS and controlled by the MEDIA GATEWAY CONTROLLERusing MEGACO. This complexity has further implications in terms ofcomplicating overall network design, particularly with respect to thescaling of participating network elements. Thus, as a consequence of itsinordinate complexity, the NGN architecture brings with it a number ofvery significant implementation considerations that may be summarized asfollows:

[0050] Potential poor performance resulting from the high processingoverhead: network functionality is highly decomposed into distributednetwork elements that must communicate through the network itself usingvarious protocols;

[0051] Numerous indeterminate scaling relationships that introduce aproportionally larger number of potential bottlenecks;

[0052] Troubleshooting procedures that must isolate and resolve problemsthat appear to reside in more than one place do to protocolincompatibilities;

[0053] Software integration requirements that are difficult for mostcarriers to support.

[0054] It is the conclusion of this analysis that the NGN architectureas represented in FIG. 2 has too many moving parts to operateefficiently. Attempts to remedy these limitations ultimately translateinto implementation cost for the carrier attempting to deploy an NGN.

Insufficient Support For New Services Confounds NGN Deployment

[0055] The NGN architecture suffers from insufficient support for newservices. It largely replicates the telephone-oriented feature set oftoday's PSTN. Due to the centralized control model of the NGN, supportfor new network services is dependent upon the ability of the MEDIAGATEWAY CONTROLLER and APPLICATION SERVERS to provide the features thatcomprise a network service. Much like with the PSTN, feature delivery bya centralized controlling entity is limited by the carrier's ability(and willingness) to modify the controlling entity to provide newservices. Notwithstanding the NGN vision of third-party applications andnew services supported through MEDIA GATEWAY CONTROLLER APIs, as apractical matter it is a tenuous proposition to modify access to it, oradd to its service load once it has been optimized to deliver aparticular portfolio of services.

[0056] Beyond risks related to destabilizing the core of the network byproviding API access to the MEDIA GATEWAY CONTROLLER, the genericconcept of using APIs to integrate application services came intoquestion some time after the inception of the NGN and its API-basedstrategy. In actual practice—“actual practice” being a function ofindustry consensus derived from years of internet experience—third-partyapplications offered through the NGN are probably better integratedusing standard IP-based IETF protocols such as SIP and HypertextTransfer Protocol. APPLICATION SERVER integration into the PACKETTRANSPORT NETWORK using internet-style protocols (based on messagepassing) has proven far more flexible and cost-effective thanintegrations based on APIs. APIs tend to be highly vendor-specific,programming language-specific, and, since they are based fundamentallyon function calls rather than message sets, tend to be less tolerant ofpartial implementation.

[0057] Notwithstanding the foregoing, it should be kept in mind thatnetwork signaling protocols like SIP are not compatible with thedevice-oriented MEGACO protocol used to control telephones connected toRESIDENTIAL GATEWAYS. Thus, as pointed out earlier in the discussion,the two-tiered signaling model of the NGN puts the MEDIA GATEWAYCONTROLLER into a mediation role, performing an imperfect translationbetween its use of MEGACO to control service delivery to telephones andits use of SIP as the means to access application services.

[0058] Interactive calling services were originally envisioned thatwould provide the NGN subscriber with the ability to select or customizecall processing logic, perhaps even to enable interoperability betweennetwork features and application programs running on the subscriber'spersonal computer (e.g. active browser sessions, instant messagingclients) or to access subscriber-specific data objects (e.g. contactlists, call logs, content subscriptions). Implementation of these typesof interactive calling services using only AIN-style APIs was eventuallyperceived as largely impractical in the NGN because the MEDIA GATEWAYCONTROLLER (supporting the APIs) would be required to access, manage,and execute unique, complex service logic for very large number ofsubscribers at the same time. The following points illustrate othersignificant limitations of the NGN with respect to supporting newservices:

[0059] In the NGN, the MEDIA GATEWAY CONTROLLER delivers telephonefeatures by remotely controlling the RESIDENTIAL GATEWAY. It can onlydeliver features through a RESIDENTIAL GATEWAY whose feature set itfully understands according to the MEGAGO standard. This factor imposessubstantial constraints on the variety of network services the NGN candeliver because it is impractical or unfeasible to control an endpointfeature set that extends beyond that anticipated by MEGACO.

[0060] Calling services that perform call control operations require afull knowledge of subscriber Class of Service parameters and servicedelivery preferences. This information governs not only the subscriber'sability to invoke the calling service in the first place, but the uniquebehavior of the service when invoked by that particular subscriber. Mostof the information that interactive calling services (e.g. call logfunctions, programmable call-blocking and call-forwarding) require isburied somewhere deep inside the NGN infrastructure in much the same waythat it was buried inside the CENTRAL OFFICE SWITCH in the PSTN. Thisfactor imposes substantial constraints on the variety of networkservices the NGN can deliver because call log entries and relatedsubscriber-specific network usage data are largely unavailable forreal-time access by third-party applications.

[0061] RESIDENTIAL GATEWAYS are unintelligent in the sense that theyrequire the MEDIA GATEWAY CONTROLLER to mediate all network signalingfunctions on their behalf. They cannot determine the broader networksignaling context of the calling operations in which they participate.They are incapable of independently executing service logic thatinvolves network signaling operations (e.g call redirection, multipointcall control, call supervision, multiple line appearances, etc.) withoutcentralized participation by the MEDIA GATEWAY CONTROLLER. These factorsimpose substantial constraints on the variety of network services theNGN can deliver because each new service must be tightly integrated withthe MEDIA GATEWAY CONTROLLER in order to perform call controloperations.

[0062] To work around these constraints, recent approaches to offeringnew services in the NGN have put an application between the RESIDENTIALGATEWAY and the MEDIA GATEWAY CONTROLLER. The application is responsiblefor controlling the subscriber's telephones, giving them access tovarious new features. These approaches support: (a) a variety oftelephone types not supported by standard MEGACO; (b) better access tocall log records and related subscriber-specific network usage data; and(c) the ability to execute user-configurable service logic not supportedby the MEDIA GATEWAY CONTROLLER.

[0063] As an example of this approach, companies such as Cisco,Broadsoft, LongBoard, and Sylantro have built application systems thatprovide optimized combinations of business telephone services thatinclude PBX and Centrex features. While some of these solutions aredesigned for enterprise deployment, those intended for carrierdeployment are often referred to using the moniker “IP Centrex.” IPCentrex solutions provide calling services and telephone features usingvarious brands of office telephones and web browser-based graphical userinterfaces. Generically, IP Centrex solutions equate to a network-basedsoftware PBX application that replaces much of the functionality of theMEDIATE GATEWAY CONTROLLER.

[0064] IP Centrex solutions are often referred to in the industry as“point solutions.” Point solutions enable the carrier to provide a veryparticular set of new services for isolated populations of subscribers.They are a work-around bourne out of necessity and introduce additional“non-standard” intermediary network elements into the NGN. Adding newnetwork elements of this type brings with it significant scalingimplications associated with carrier deployment of a service that cannotscale as the network itself scales. Point solutions are operationallyunfeasible for carriers serving tens of millions of subscribers becausethe feature set of the point solution cannot be managed as a standardnetwork feature set that may be enabled or disabled for any subscriberat will. If such a service became popular, the carrier would have toreplicate many instances of the system—potentially thousands ofthem—each to serve a certain critical mass of subscribers, and then tomanage these systems as independent islands of service deliverycapability.

[0065] As summarized below, point solutions bring with them their ownunique set of carrier deployment challenges and at the same time do notresolve the general limitations of the NGN with respect to supportingnew services:

[0066] Point solutions do not in a general sense enable the NGN tocontrol a telephone feature set (or other endpoint device feature set)that extends beyond that anticipated by MEGACO, but instead supportsselected vendor telephones in a way that suits their own specificpurposes.

[0067] Point solutions do not in a general sense make call log recordsand related subscriber-specific network usage data available forreal-time access by a third-party applications, but instead simply storeit internally for their own use.

[0068] Point solutions do not in a general sense make it possible forthird-party applications to perform call control operations, but insteadimplement call control operations for their own specific purposes.

NGN Support For Multi-Service Delivery

[0069] The NGN architecture leaves to future consideration features setsthat extend beyond traditional PSTN voice services. It assumes centraloffice (or equivalent) deployment for most network elements and that theRESIDENTIAL GATEWAY is providing telephone service over ageneral-purpose PACKET TRANSPORT NETWORK that supports QoS. Video anddata services are not addressed directly by the NGN, and it is assumedthat other network elements and related infrastructure components willprovide these services independently.

[0070] The above assumptions do not anticipate that the subscriberpurchasing voice services is also likely to purchase data and videoservices from the same carrier. When the carrier's primary connection tothe subscriber premise is through a broadband access network, it quicklybecome impractical to install a separate physical connection orindependent solution for each type of media service offered to thatsubscriber. Much of the motivation behind the transition to a convergednetwork is based on the notion that multiple services—voice, video, anddata services—can be offered to a network subscriber through a single IPdata path to the premise. The converged vision extends to enablingcarriers to combine several media types into a comprehensive networkservices offering.

[0071] This type of multi-service delivery requires QoS arbitration atthe subscriber premise so as to ensure QoS for all voice, video, anddata terminal devices (i.e. telephones, televisions, PCs) installedthere; all of these terminal devices may be operating at the same timesharing the same IP data path. Many potential new services anticipateproviding value to subscribers because of their ability to supportmultiple media types at the same time, potentially integrating twoservices that support different media types in a way that makes eachmore useful. In addition, voice, video and data terminal devicesinstalled at the subscriber premise often support different controlinterfaces that must be normalized to network signaling and devicecontrol conventions that would enable them to interact withnetwork-based APPLICATION SERVERS in a consistent fashion.

[0072] Equipment vendors have responded to requirements to enable NGNmulti-service delivery through a single IP data path to the subscriberpremise by creating an integrated access device (IAD). The IAD beganlife as specialized version of a RESIDENTIAL GATEWAY, designed as ameans to enable subscribers to connect voice and data terminals at thepremise in such fashion as they may share a common IP data path to thecarrier's PACKET TRANSPORT NETWORK. The IAD marketplace today offers thecarriers a bewildering assortment of devices, targeting optimalcombinations of cost effectiveness and/or feature richness.

[0073] Some IADs support voice-over-IP and QoS arbitration featureswhereas others attempt to obviate total reliance on remote IAD controlby a MEDIA GATEWAY CONTROLLER (using MEGAGO) by implementing selectedPOTS telephone features and SIP network signaling within the IAD. SomeIADs used by the cable industry do not support VoIP in the NGN sense ofit, but instead provide for “voice-over-broadband.” The termvoice-over-broadband refers to a family of proprietary access networkdesigns, the most common of which is that used by cable companies thattransport voice, as well as data and video, on distinct broadbandchannels created through frequency division multiplexing (FDM). In thistype of voice-over-broadband network, voice and data flows are split atthe central office (or central office equivalent), with the voice pathconnecting to a CENTRAL OFFICE SWITCH (usually through a GR 303 packetinterface). IADs of this type are excepted from this discussion becausethey do not support the converged “end-to-end IP” vision of the NGN andare fundamentally incompatible with it.

[0074] NGN voice services offered through an IAD using VoIP arevirtually identical to voice services offered directly through a POTSline connected to a CENTRAL OFFICE SWITCH. Typically, the IAD is used toconnect telephones and computers to a broadband data service provided tothe premise. Through the gateway facilities of the IAD, voice and dataare transported as distinct packet flows over a common IP data path thatis contiguous (from an IP connectivity standpoint) with the PACKETTRANSPORT NETWORK. In the NGN, the feature set of the CENTRAL OFFICESWITCH is emulated by the MEDIA GATEWAY CONTROLLER in concert with anumber of other network elements such as a “feature server.”Conceptually, in the NGN the IAD functions exactly as any otherRESIDENTIAL GATEWAY.

[0075] Unable to deliver traditional PSTN network servicesindependently, and devoid of the ability to enable compelling newservice capabilities, the value proposition of the IAD lies in itsability to enable the subscriber to use one physical line (e.g. DSLline, cable, T1) for both voice and data at the same time. In summary,the cost of the IAD must be compared to the cost of simply installingseparate voice and data lines to the premise.

[0076] After substantial field experience, technical staff at two majorUnited States Local Exchange Carriers recently concluded that the costfor them to deploy network services using an IAD is greater than orequal to the cost to deploy separate voice and data lines to thepremise, except in rare cases where it would be exceptionally expensiveto bring in an additional line. Despite wide availability several foryears, the limited deployment of IADs further suggests that the NGN hasbeen a victim of failed economics. From a pure technical perspective, anIAD may be an appropriate “edge device” form-factor to address MEGACOrequirements for multi-service delivery to the subscriber premise. Thisobservation does not remedy the underlying problem that its cost todeploy is perceived as more than can be justified by the modestfunctionality it enables.

SUMMARY An Edge Switched Network Architecture

[0077] An Edge Switched Network (ESN) architecture is introduced as aninnovation whose implementation is dependent upon the Distributed EdgeSwitch (the “invention” that is the subject of this disclosure). Thegeneral operating principles of the ESN are described below as a pretextto a detailed description of the Distributed Edge Switch (DES) found inthe OVERVIEW section. It will be shown that the ESN resolves many oflimitations inherent to the NGN.

[0078]FIG. 3 depicts an ESN architecture principally comprised of“connectivity elements.” A connectivity element is a particular type ofnetwork element that is capable of participating in call sessions usingSIP network signaling and RTP bearer transmission. Communities ofconnectivity elements communicate in a peer-to-peer fashion withoutnecessarily requiring assistance from the network beyond IPconnectivity. The three connectivity element types defined for the ESNare as follows:

[0079] EDGE SWITCH

[0080] APPLICATION SERVER

[0081] PSTN GATEWAY

[0082] All three connectivity elements share a similar network interfacedesign that combines support for SIP network signaling, RTP bearertransport, media encoding/decoding, and event-driven call processinginto a single intelligent endpoint device. From a conceptual standpoint,each connectivity element collapses functionality from each major NGNnetwork element into a self-contained whole capable of “intelligentparticipation” in call sessions. Intelligent participation refers to theability of a connectivity element to operate both as SIP networksignaling endpoint and as a call control agent capable complex callcontrol operations. Complex call control operations might involvesupervising call sessions that contain multiple call legs extending toother connectivity elements. Connectivity elements may leveragenetwork-based SIP proxy servers to support these and other complexoperations.

Role of the Edge Switch in the ESN

[0083] The EDGE SWITCH is an ESN connectivity element whose principalfunction is to support the delivery of voice, video (multimedia) anddata services—multi-service delivery—to the subscriber premise through ashared IP data path. It aggregates several functions together into asingle, cost-effective device that is deployed by the carrier as apremise-based network element.

[0084]FIG. 3 shows that the EDGE SWITCH functions as a broadband accessnetwork termination device (e.g. DSL modem, cable modem, T1 terminator,passive optical terminator) at the subscriber premise, providing an IPdata path from the premise to the PACKET TRANSPORT NETWORK. It alsoprovides a means by which voice, video and data terminals at thesubscriber premise may connect to other network endpoints in the PACKETTRANSPORT NETWORK, each creating connections through a shared, routed IPdata interface.

[0085] Ultimately, all subscriber terminals plugged into the EDGE SWITCHcommunicate with the PACKET TRANSPORT NETWORK through QoS routingcapabilities built into the EDGE SWITCH. EDGE SWITCH routingcapabilities enable QoS arbitration at the exact point where subscriberterminals interface the broadband access network. Video streamingservices deployed within the network are made accessible to SIP mediastreaming devices connected to the EDGE SWITCH (such as SIP-enabledset-top boxes). Data transmission capacity not used for voice telephonecommunications or media streaming is made accessible to data terminalsfor data communications. The EDGE SWITCH operates as a MEDIA GATEWAY tothe extent that it is able to present POTS or other types of non-SIPtelephones (connected through its LINE interface) to the network as SIPnetwork signaling endpoints. The EDGE SWITCH provides necessary terminaladaptation as necessary for the conversion of device signaling andbearer channel content at the LINE interface to/from SIP networksignaling and RTP voice transmission conventions required by the ESN.

[0086] The EDGE SWITCH executes locally stored call processingapplications in response to detecting network trigger events. In thisway, voice telephone features and related calling services are providedby the EDGE SWITCH to the subscriber through legacy POTS and/or IPtelephones, without the participation of centralized network controlelements.

[0087] In order to perform in the capacities described above, the EDGESWITCH must operate as a general computing device able to executecomplex software programs and store relatively large amounts ofinformation. More specifically, the EDGE SWITCH contains the following:

[0088] Sufficient computing capacity, memory, and operating systemfunctionality necessary to support application-level program developmentand application program execution; particularly the execution of callprocessing applications;

[0089] Sufficient storage capacity to hold an operating event history ofa year or more; operating events include configuration changes and allpotentially billable subscriber access to calling services (e.g. calllog records);

[0090] Sufficient storage capacity to hold all call processingapplication executable code needed to support network service deliveryaccording to the subscriber's Class of Service;

[0091] Sufficient storage capacity to hold local call routes and networkaddressing information needed to support network service delivery (viacall processing applications) for all subscribers served by the EDGESWITCH;

[0092] Sufficient storage capacity to hold subscriber Class of Serviceparameters and service delivery preferences needed to govern thesubscriber's ability to invoke a particular calling service and theunique behavior of the service when actually invoked.

[0093] System software to support a SIP network signaling protocol stackthat can be programmed to selectively expose trigger points in a callthat automatically invoke service logic (i.e. call processingapplications).

[0094] System software to support centralized service provisioning,device management, and software upgrades by a remote system managementplatform

[0095] System software to support the full complement of QoSarbitration, including traffic classification, packet labeling, packetscheduling, and admission control based on subscriber Class of Service.

[0096] System software to support real-time remote monitoring of networkservice delivery, with active reporting of status to a remote systemmanagement platform.

[0097] System software required to meter network service delivery bygenerating call log records and to store them in a database internal tothe EDGE SWITCH.

[0098] System software required to normalize vendor-specific terminaldevice interfaces to comply with network signaling and device controlconventions that would enable them to interact with network-basedAPPLICATION SERVERS in a consistent fashion.

[0099] Secure data exchange interfaces that make EDGE SWITCH featuresand all information stored within its internal databases accessible toremote database clients, network management systems, and third-partyapplications.

Role of the Application Server in the ESN

[0100] The APPLICATION SERVER is an ESN connectivity element whoseprincipal function is to support the delivery of network services toother ESN connectivity elements. As is common to all ESN connectivityelements, the APPLICATION SERVER is capable of intelligent participationin call sessions. It can execute internally stored call processingapplications (service logic) in response to network signaling events andrelated trigger points in a call. An example of signaling events thatwould trigger service logic execution include an attempt by a SIPsignaling endpoint to connect to the APPLICATION SERVER or disconnectfrom it once connected. Trigger points in a call might include eventsdetected while the SIP call session is in progress, such as mid-sessioncontrol messages or certain call control operations.

[0101] In most scenarios, network services or features supported by anAPPLICATION SERVER are rendered directly to SIP network signalingendpoints that connect to it. For reasons of security and protocolcompatibility, the APPLICATION SERVER may implement secure connectionpolicies that prohibit access to SIP network signaling endpoints thatare not directly managed or mediated by another ESN connectivityelement. For example, a PC-based SIP client attempting to connect to theAPPLICATION SERVER through the public internet may be prohibited fromdoing so; however, a PC-based SIP client attempting to connect to theAPPLICATION SERVER through an EDGE SWITCH will have its SIP signalingmediated by that EDGE SWITCH—perhaps encrypted according to an internalcarrier network standard—and as a result may be allowed to connect tothe APPLICATION SERVER in this way.

[0102] Upon detecting a SIP call session initiation, the APPLICATIONSERVER examines SIP signaling information and compares it with what itknows internally about the calling party so that it may automaticallydetermine the feature, function, or service that it should render to thecalling party. For example, if the calling party is a SIP networksignaling endpoint (SIP User Agent) used by an EDGE SWITCH to representa POTS telephone at the subscriber premise, the APPLICATION SERVER willreceive the dialing number of the calling party (i.e. the dialing numberassigned to the POTS telephone originating the call). It may then usethis dialing number to access an internal database for the purpose ofretrieving the Class of Service parameters associated with this dialingnumber. Class of Service parameters will inform the APPLICATION SERVERas to whether or not it should render its service to the calling party.

[0103] Aside from the number of simultaneous SIP call sessions it canpotentially support—a function of its hardware form-factor—there is afundamental difference between the APPLICATION SERVER and the EDGESWITCH: whereas the APPLICATION SERVER renders network services andfeatures to a calling party, the EDGE SWITCH renders network servicesand features to terminal devices plugged into it at the subscriberpremise.

[0104] In rendering network services and features to a calling party,the APPLICATION SERVER exploits the capabilities of various systemresources. Call processing applications executing on the APPLICATIONSERVER may perform database queries, media store-and-forward operations,support group conferencing, convert text to speech, recognize voicecommands, or any one of a number of operations that might be beyond thescope of what an EDGE SWITCH could perform without assistance from thenetwork. By simply connecting to an APPLICATION SERVER, an EDGE SWITCHor PSTN GATEWAY may request and receive the intelligent participation ofthe APPLICATION SERVER when they require such assistance.

Role of the PSTN Gateway in the ESN

[0105] The PSTN GATEWAY is an ESN connectivity element whose principalfunction is to (a) make it possible for the EDGE SWITCH to connect toPSTN endpoints using SIP network signaling and (b) to make it possiblefor PSTN endpoints to connect to the EDGE SWITCH using PSTN networksignaling. The PSTN GATEWAY combines the functions of the NGNarchitecture's SIGNALING GATEWAY, TRUNK GATEWAY, and MEDIA GATEWAYCONTROLLER so as to enable SIP call sessions connecting to it to bebridged to PSTN endpoints. It provides necessary signaling gatewayfunctions as required to interface the PSTN using SS#7 protocols. Italso provides necessary media gateway functions to convert bearerchannel encoding formats at the TRUNK interface to/from SIP and RTPvoice transmission conventions required by the ESN.

[0106] A connection attempt that originates in the ESN and that isintended to ultimately connect to a PSTN endpoint, will be directed to aSIP network signaling endpoint on a PSTN GATEWAY. The PSTN GATEWAY willinitiate essentially the same workflow sequence used by the APPLICATIONSERVER to execute internally stored call processing applications.Consistent with its specialized role in the ESN, the PSTN GATEWAY willexecute a call processing application that will connect the incoming SIPcall session through to the specified PSTN endpoint. Thus, an incomingSIP call from the ESN to the PSTN GATEWAY will initiate a correspondingPSTN call set-up to a PSTN endpoint through the TRUNK interface. In thereverse direction, an incoming PSTN call through the TRUNK interfacewill result in a SIP call set-up to a SIP network signaling endpoint inthe PACKET TRANSPORT NETWORK.

Architectural Comparison of ESN to NGN

[0107] The ESN is substantively different from the NGN in a number ofsignificant ways, and as a result of these differences, the ESN remediescertain architectural limitations inherent to the NGN as set forth inthe foregoing sections. By showing how specific limitations of the NGNare resolved by the ESN, the summary below affords an opportunity tohighlight important capabilities inherent to the ESN architecture withina relevant context:

[0108] (1) The potential poor performance of the NGN resulting from highprocessing overhead for distributed elements communicating through thenetwork (and attendant scaling problems related thereto) is resolved bythe following:

[0109] Eliminating the MEDIATE GATEWAY CONTROLLER function entirely, andinstead distributing call processing capability throughout the networkby embedding it in intelligent endpoint devices;

[0110] Feature-oriented network service delivery to subscribers throughterminals at the premise is performed by dedicated computing resourcesphysically located on the subscriber premise (i.e. by the EDGE SWITCH);

[0111] To the extent that the above method of feature delivery does notrequire assistance from the network for most call processing functions,feature responsiveness is perceived by ESN subscribers to be essentiallyinstantaneous, regardless of the number of simultaneous ESN networkusers;

[0112] As a consequence of eliminating the MEDIA GATEWAY CONTROLLERfunction entirely, so too is the gateway control layer eliminated,effectively flattening the two-tiered NGN network signaling model into anormalized SIP network signaling model. According to the normalized SIPnetwork signaling model, voice and multimedia connections areestablished peer-to-peer using the same method;

[0113] As a result of flattening the two-tiered NGN network signalingmodel into a normalized SIP network signaling model, overall ESN systemperformance with respect to APPLICATION SERVER access by EDGE SWITCHESand PSTN GATEWAYS is dramatically enhanced. The delivery ofnetwork-based features provided by APPLICATION SERVERS in the ESN isperceive by subscribers to be essentially instantaneous and relativelyunaffected by the number of simultaneous ESN network users.

[0114] (2) The NGN's large number of potential bottlenecks that areintroduced as a result of its numerous indeterminate scalingrelationships are resolved by the following:

[0115] Reducing the number of network elements that are needed toparticipate in network service delivery;

[0116] Embedding feature delivery and service metering functions intothe network access device (EDGE SWITCH or PSTN GATEWAY) so as toeliminate requirements for the centralized network elements to retaininformation about the state of any given call.

[0117] (3) Troubleshooting procedures for the NGN must isolate andresolve problems that appear to reside in more than one place because ofprotocol incompatiblities. This issue is resolved in the ESN by thefollowing:

[0118] Reducing the total number of protocols;

[0119] Reducing the total number of network elements.

[0120] Managing all connectivity elements as populations of likeelements, each of which supports more or less identical provisioning,device management, diagnostic, and event reporting mechanisms, and eachusing the same interface protocols to support similar tasks.

[0121] (4) Software integration requirements for the NGN are difficultfor most carriers to implement and support. This issue is resolved inthe ESN by the following:

[0122] Supporting a hardware scaling model in which ESN service deliverycapability is built up in a predictable, linear fashion by replicatingconnectivity elements;

[0123] Embedding most subscriber-oriented features into a very low-costdevice (EDGE SWITCH) that is physically replaced if an error conditionis detected rather than repaired; the replacement unit is thenautomatically detected and re-synchronized with a system managementplatform so that identical network service capabilities are restored tothe subscriber;

[0124] Requiring relatively few centralized software processes tosupport feature-oriented network service delivery, as compared to theNGN;

[0125] Utilizing SIP-based access to service logic running withinAPPLICATION SERVERS for advanced feature support—a method that sharplycontrasts with NGN support for API access to call processingcapabilities within the MEDIA GATEWAY CONTROLLER.

[0126] (5) The economic model for the NGN that has not proved compellingto carriers largely due to high implementation costs resulting from itsinordinate complexity. The relative simplicity of the ESN translatesinto a lower relative cost for greater network service deliverycapability, thereby increasing the likelihood that its economic modelwould be compelling enough to motivate carrier implementation. Some ofthe principal reasons for its simplicity relative to the NGN include thefollowing:

[0127] The ESN is capable of delivering traditional PSTN networkservices and new multi-service capabilities through a common means withlittle or no reliance on feature-controlling infrastructure in thecentral office;

[0128] The ESN employs a hardware scaling model that uses primarily massproduced, low-cost EDGE SWITCHES for most of its subscriber-orientedservice delivery;

[0129] The ESN requires dramatically less effort to test compared to theNGN, since validating the feature set of a single EDGE SWITCH for acertain number of concurrent sessions confers validation of the abilityto support any multiple of that certain number of concurrent sessions bydeploying a proportionate multiple of additional EDGE SWITCHES;

[0130] The ESN enjoys very low implementation costs due to the fact thatits network integration is based on relatively few protocols other thanSIP. The MEGACO protocol stack is eliminated from the model, along withall attendant requirements for licensing and interoperability testingbetween MEGACO-compliant network elements.

[0131] As a consequence of these factors, overall system cost for theESN on a per-user basis has been calculated to be less expensive thanPSTN technology to provide an equivalent feature. Overall system costfor the ESN has been estimated to be less expensive than the NGN toprovide an equivalent feature.

[0132] In consideration of the above cost estimates, it should be notedthat indeterminate scaling relationships in the NGN, and the lack ofdeployed NGN networks that could be used for direct comparison, arefactors that together confound attempts to quantify the trueimplementation cost of an actual NGN deployment. A theoreticalcalculation of cost-per-subscriber (i.e. an estimate) in the NGN mightnot necessarily reflect actual feature delivery capacity because ofunanticipated effects that are likely to result from its highlydecomposed architecture.

Support for New Services in the ESN

[0133] Support for new services by the ESN is made possible because ofseveral capabilities that are inherent to its architecture. Some ofthese capabilities are described as follows:

[0134] The ESN supports voice, video and data-oriented network servicesthrough a common (i.e. shared) IP data path, providing QoS arbitrationat the premise as is required to support multi-service delivery; thus,new services can be offered for each type of media, or new services cancombine features that involve more than one type of media into a singlemultimedia service. As an example, a feature could be created to lowerthe volume of the television if someone answered the telephone;

[0135] Feature delivery by the EDGE SWITCH is remotely programmable bythe carrier; software loads can be uploaded into the EDGE SWITCH tointroduce new features over time without network infrastructure changes;

[0136] The ESN subscriber may interact with the EDGE SWITCH to selectfeatures and program them to behave according to subscriber-specificparameters, potentially to interoperate with a variety of third-partyapplications, application programs running on the subscriber's PC, or tosecurely access data objects stored in network servers or on thesubscriber's PC. As an example, an application could use instantmessaging to inform the end user as to the identity of a calling party.

[0137] Most ESN network intelligence is located within the EDGE SWITCHitself. A large part of this “network intelligence” includes the EDGESWITCH'S ability to internally store call log records and othersubscriber-specific information related to network service delivery.This stored information in effect comprises a distributed database ofvirtually unlimited scalability. New service opportunities are madepossible by virtue of the fact that this information may be securelyaccessed by an application and subsequently presented to an end userwithin the context of interactive calling services. As an example,network-based web applications may be created to provide end usersaccess to multi-year call histories managed through a web browser-basedgraphical user interface.

[0138] Because of its SIP-based network signaling model, the EDGE SWITCHcan perform complex call control operations that involve SIP networksignaling endpoints located virtually anywhere in the network. Thissupport for complex call control operations by the EDGE SWITCH in effectenables it to function as a distributed call control resource ofvirtually unlimited scalability. New service opportunities are madepossible by virtue of the fact that this capability can be securelyaccessed by an application and subsequently presented to an end userwithin the context of interactive calling services. As an example,network-based web applications may be created to provide end users theability to access EDGE SWITCH calling features through a webbrowser-based graphical user interface.

[0139] EDGE SWITCH call control operations can be used to transparentlyaccess network-based features provided by APPLICATION SERVERS. As aresult, combinations of call control features internal to the EDGESWITCH and network-based features that are external to the EDGE SWITCHcan be dynamically configured and presented together to end users as aunified service or capability—that is, presented in such a way that thesource of the feature (internal to the EDGE SWITCH or network-based) isentirely transparent to the end users. Thus, beyond its ability tosupport programmable internal feature sets via software upgrades andconfigurable call processing applications, the EDGE SWITCH feature setmay be further extended through transparent integration withnetwork-based features. As an example, an EDGE SWITCH feature may becreated to override basic dial-tone service: when an EDGE SWITCH detectsthat a telephone plugged into it went off-hook, the override featurewould forgo the basic dial-tone service and instead transparentlyconnect to a network-based voice-activated dialing application.

[0140] In general, in one aspect, the invention features a networkdevice including a plurality of communication interfaces, among whichthere is a telephone line interface, a computer data interface, and abroadband network interface. The network device also includes aprocessor; a machine-readable storage medium which during use stores acall processing application and service profiles, and which storesexecutable instructions to mediate communications between the pluralityof communication interfaces, the instructions causing the network deviceto detect network signaling events or trigger points in a telephone calland invoke the call processing application in response to the detectednetwork signaling events or trigger points, the call processingapplication operating according to parameters defined in the serviceprofiles.

[0141] Preferred embodiments include one or more of the followingfeatures. The plurality of communication interfaces further includes avideo streaming device interface. The broadband network interfaceterminates a broadband network link that joins a customer premises to apacket carrier network. The instructions further cause the networkdevice to route IP data between the computer data interface and thebroadband network interface. The network device is contained in a singlephysical enclosure. The instructions further cause the network device toprovide a first SIP proxy agent to represent a telephone that uses thetelephone line interface, and provide a second SIP proxy agent torepresent a computer that uses the computer data interface. The storagemedium stores call routing tables, and the instructions further causethe network device to perform call routing for telephone calls that usethe telephone line interface. The storage medium also stores callrouting tables, and the instructions cause the network device to performcall routing for telephone calls according to the call routing tables,the telephone calls using the telephone line interface.

[0142] In general, in another aspect, the invention features a networkdevice including a plurality of communication interfaces among whichthere is a telephone line interface, a computer data interface, and abroadband network interface. The network device also includes aprocessor; a machine-readable storage medium which during use storescall routing tables, and which stores executable instructions to mediatecommunications between the plurality of interfaces, the instructionscausing the network device to perform call routing according to the callrouting tables, the telephone calls using the telephone line interface.

[0143] Preferred embodiments include one or more of the followingfeatures. The call routing includes peer-to-peer call signaling betweencustomer premises over a shared IP network. The call signaling isperformed without requiring stateful elements of the shared IP networkabove the IP infrastructure. The broadband network interface terminatesa link that joins the network device to the shared IP network. The callrouting includes call signaling to a PSTN endpoint via a PSTN gatewaythat is reachable over the broadband network interface. The instructionsfurther cause the network device to route IP data between the computerdata interface and the broadband network interface. And the plurality ofcommunication interfaces further includes a video streaming deviceinterface.

[0144] In general, in still another aspect, the invention features anetwork device including a plurality of communication interfaces, amongwhich there is a telephone line interface, a computer data interface,and a broadband network interface. The network device also includes aprocessor; and a machine-readable storage medium which stores executableinstructions to mediate communications between the plurality ofinterfaces, the instructions causing the network device to log atelephone event record to a telephone event repository, the event recorddescribing a telephone call communication mediated by the networkdevice.

[0145] Preferred embodiments include one or more of the followingfeatures. The telephone event repository can be included in the networkdevice or be remote relative to the network device. The network deviceis housed in a single physical enclosure.

[0146] In general, in still yet another aspect, the invention features anetwork device includes a broadband network interface; a plurality ofinterfaces, among which there is a telephone line interface and acomputer data interface; a processor; and a machine-readable storagemedium that stores processor-executable instructions to provide proxyagents. The instructions cause the network device to provide a telephoneSIP proxy agent to represent a non-SIP telephone that uses the telephoneline interface; provide a distinct SIP proxy agent for each additionaldevice that uses an interface in the plurality of interfaces; and causethe network device to implement a proxy server that mediates all SIPcommunications over the broadband network interface involving thenon-SIP telephone and the each additional devices.

[0147] In general, in another aspect, the invention features a methodfor establishing a voice-over-packet network architecture. The methodincludes locating a system management platform in a shared packetnetwork, the system management platform collecting call log data from aplurality of network devices; and distributing the plurality of networkdevices that each include a telephone line interface, a computer datainterface, a broadband network interface terminating a link from theshared packet network, a processor, and a machine-readable storagemedium storing processor-executable instructions to control telephonecalls, the instructions causing each network device to route telephonecalls in a peer-to-peer fashion over the shared packet network and tosend call log data to the system management platform.

[0148] The details of one or more embodiments of the invention are setforth in the accompanying drawings and the description below. Otherfeatures, objects, and advantages of the invention will be apparent fromthe description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS Conventions

[0149] Figures utilize a dotted-decimal number scheme to identify systemelements using a bracket notation shown as “[number].” The decimal isused to denote a sub-element dependency. Programmatic relationships andcall signaling pathways are numbered using a curly brace notation shownas “{number}” where the number is a tag used to identify theserelationships and pathways in the discussions and do not imply order ofoperations. With respect to the relationship between network elementsand network connectivity clouds shown in the figures, solid connectorlines denote physical network interfaces whereas dotted lines denotemessage-passing protocol relationships in which protocol data units areexchanged through an IP data path. Many discussions will applyterminology based on the seven layer Open System Interconnection (OSI)Reference Model.

[0150] A DEFINITIONS section provides detailed descriptions of selectedterms and system elements as they pertain to the invention. TheDEFINITIONS section follows the OVERVIEW section. System elements thatare depicted in figures will show a number identifier in brackets sothat they may cross-referenced.

Table of Figures

[0151]FIG. 1 shows the structure of PSTN and AIN with Signaling,Transport, and Service Control.

[0152]FIG. 2 shows a Next Generation Network Architecture.

[0153]FIG. 3 shows An Edge Switched Network Architecture.

[0154]FIG. 4 shows A Distributed Edge Switch.

[0155]FIG. 5 shows the Edge Switch Hardware Architecture.

[0156]FIG. 6 shows the Edge Switch Software Architecture.

[0157]FIG. 7 shows the Edge Switch Call Model.

[0158]FIG. 8 shows the Distributed Edge Switch Carrier Network ReferenceArchitecture.

[0159]FIG. 9 shows the Distributed Edge Switch System ManagementWorkflow.

[0160]FIG. 10 shows the Distributed Edge Switch Call Signaling Workflow.

[0161]FIG. 11 shows the Distributed Edge Switch as Distributed SIP ProxyServer.

[0162]FIG. 12 shows the Distributed Edge Switch Network Service DeliveryWorkflow.

[0163]FIG. 13 shows an Edge Switch For Residential Subscriber DeploymentUsing VDSL Broadband Access Network

[0164] Like reference symbols in the various drawings indicate likeelements.

DETAILED DESCRIPTION Overview

[0165] The DES described below is new whereas the PSTN GATEWAY andAPPLICATION SERVER elements of the ESN are assumed to represent existingspecific categories of network elements originally designed forintegration into the NGN. Since they present themselves to the networkas SIP network signaling endpoints, they are also suitable fordeployment within the ESN.

[0166] In the ESN architecture, the EDGE SWITCH serves as the means todeliver network services to subscribers. The DES is an implementation ofthe EDGE SWITCH described for the ESN, and thus should be viewed as itsfunctional equivalent. While the BACKGROUND section focused on the roleof a generic EDGE SWITCH in the ESN, this OVERVIEW section, inconjunction with the DEFINITIONS section and FIGS. 4-11, providessufficient technical information necessary to implement an actual EDGESWITCH in the form of a DES. Most detailed technical descriptions ofhardware and software subcomponents, and their detailed functionalcontributions, are contained with the DEFINITIONS section. This OVERVIEWsection will focus on articulating their respective roles as DES systemelements with the architectural context of the ESN.

[0167]FIG. 13 depicts an embodiment of an actual EDGE SWITCH design thatis suitable for residential subscriber deployment using a DigitalSubscriber Line (DSL) connection to a broadband broadband accessnetwork.

[0168]FIG. 4 depicts the two basic elements that comprise the DES: theEDGE SWITCH [1] and the SYSTEM MANAGEMENT PLATFORM [2]. As shown, theSYSTEM MANAGEMENT PLATFORM [2] resides within the IP CARRIER NETWORK [6]whereas the EDGE SWITCHES [1] are deployed at the subscriber (customer)premise. A description of these individual elements may be found in theDEFINITIONS section.

[0169]FIG. 4 shows network elements of the DES apart from the fullcomplement of those shown for the ESN architecture; as a result, FIG. 4serves to aid in understanding the DES itself.

Form-Factor Considerations

[0170] The EDGE SWITCH [1] can be constructed to support any number ofform-factors, depending upon the transmission capacity of the BROADBANDACCESS NETWORK [6.1] and the number of TELEPHONE STATIONS [3] andSET-TOP BOXES [4] the designer believes is appropriate for a singleinstance of an EDGE SWITCH [1]. FIG. 4 depicts three distinctform-factors, with EDGE SWITCHES [1] labeled A, B, and C supporting 1,4, and 8 TELEPHONE STATIONS [3] respectively.

[0171] The choice of form-factor will effect the ratio of TELEPHONESTATIONS [3] to COMPUTER WORKSTATIONS [5]. Regardless of the number ofTELEPHONE STATIONS [3] supported by a given EDGE SWITCH [1] form-factor,one instance of an EDGE SWITCH [1] will support only one COMPUTER DATAINTERFACE [4]. This circumstance results because the basic design of theEDGE SWITCH [1] is to manage all of the transmission capacity for asingle physical connection to the BROADBAND ACCESS NETWORK [6.1], and tomanage it as a shared IP data path for use by all terminal devicesconnected to it. Any transmission capacity that is not used for voiceand video call sessions is made available for common data transportthrough the COMPUTER DATA INTERFACE [4]. As shown for the EDGE SWITCHES[1] labeled B and C, an ETHERNET HUB [9] may be plugged in place of aCOMPUTER WORKSTATION [5] for the purpose of distributing data service toseveral COMPUTER WORKSTATIONS [5].

Data Service Aggregation

[0172] Any number of EDGE SWITCHES [1] may be deployed at a singlesubscriber premise. If the subscriber has more TELEPHONE STATIONS [3] orSET-TOP BOXES [4] than can be supported by a single EDGE SWITCH [1],another EDGE SWITCH [1] is connected to the BROADBAND ACCESS NETWORK[6.1] to enable more TELEPHONE STATIONS [3] and/or SET-TOP BOXES [4] tobe plugged in. Deploying more than one EDGE SWITCH [1] at the samepremise may require that the COMPUTER DATA INTERFACES [1.4] areaggregated together into a single data service—the subscriber is likelyto want all COMPUTER WORKSTATIONS [5] at the premise to beinterconnected through a common local area network (LAN) with a singleuplink to the public network (i.e. Internet).

[0173] For purposes of data service redundancy and increased bandwidth,many businesses aggregate a number of BROADBAND ACCESS NETWORK [6.1]connections into a single data service to which they connect their LAN,usually through a router. In the example above (in which more than oneEDGE SWITCH [1] is used to support more TELEPHONE STATIONS [3] than canbe supported by one EDGE SWITCH [1] alone), a low-cost aggregationrouter may be installed to load-balance LAN access to the public networkevenly across the COMPUTER DATA INTERFACES [1.4]. To achieve thisconfiguration would be a cable plug-in operation: the LAN side port ofthe aggregation router would be connected to the LAN hub; uplink portson the aggregation router would connect it to the COMPUTER DATAINTERFACES [1.4].

Modes of Communication

[0174] Because all of the EDGE SWITCHES [1] are connected to an IPCARRIER NETWORK [6], and because each EDGE SWITCH [1] supports callsessions using SIP network signaling, the communications between EDGESWITCHES [1] is for the most part peer-to-peer. Excepting thecircumstance in which a call session has one of its endpoints in anetwork other than the IP CARRIER NETWORK [6] (i.e. PSTN), a SIP networksignaling endpoint at one EDGE SWITCH [1] simply “invites” a SIP networksignaling endpoint at another EDGE SWITCH [1] to joint it in a callsession. Usually, the participating endpoints negotiate to create voiceor video (multimedia) streams between them.

[0175] Communications between TELEPHONE STATIONS [3] are usually basedon E.164 dialing number addressing. The EDGE SWITCHES [1] perform thenecessary conversion (using network-based resources) to dynamicallyassociate a dialing number with an IP address, as required to set-up theSIP call session. Communications between SET-TOP BOXES [4] may be basedon E.164 dialing number addressing or some other carrier-specific namingor addressing convention. SET-TOP BOXES [4] typically connect to a SIPAPPLICATION SERVER and thus may use a different scheme.

[0176] Communications between COMPUTER WORKSTATIONS [5] are based onIP-based data communication protocols. The EDGE SWITCH [1] takes anactive role in non-SIP data communications initiated by COMPUTERWORKSTATIONS [5] plugged into the COMPUTER DATA INTERFACE [1.4]. Datacommunications through the EDGE SWITCH [1] are filtered through aprogrammable firewall feature set internal to the EDGE SWITCH [1] andNetwork Address Translation (NAT) services may also be applied. Inaddition, the EDGE SWITCH [1] performs QoS arbitration between allterminals competing for broadband access network transmission capacity,and as a result may attenuate the flow of IP packets available for datacommunications as transmission capacity is dynamically reserved forvoice and video transmission.

Edge Switch Hardware Architecture

[0177]FIG. 5 depicts a generalized hardware architecture for the EDGESWITCH [1]. The BROADBAND NETWORK INTERFACE [1.1] physically connects(OSI Layer 1) the EDGE SWITCH [1] to the BROADBAND ACCESS NETWORK [6.1].Its ultimate role is to provide a datalink communication path throughthe BROADBAND ACCESS NETWORK [6.1] (OSI Layer 2) to the routed IPCARRIER NETWORK [6] (OSI Layer 3). Inside the EDGE SWITCH [1] itself,the BROADBAND NETWORK INTERFACE [1.1] ultimately presents an IP datapath in the network layer to the IP ROUTING MODULE [1.2] (OSI Layer 3).The physical connection provided by the BROADBAND NETWORK INTERFACE[1.1] may serve as the DC POWER SOURCE [6.2] in some networks.Otherwise, the POWER SUPPLY [1.3] will require a DC POWER SOURCE [6.2]from the subscriber premise.

[0178] The COMPUTER DATA INTERFACE [1.4] and the VIDEO STREAMING DEVICEINTERFACE [1.5] provide physical interfaces for COMPUTER WORKSTATIONS[5] and SET-TOP BOXES [4] respectively. The TELEPHONE LINE INTERFACE[1.9] provides a physical interface for TELEPHONE STATIONS [3]. The IPROUTING MODULE [1.2] provides for QoS routing of IP packets through theCOMPUTER DATA INTERFACE [1.4] and the VIDEO STREAMING DEVICE INTERFACE[1.5]. It also provides for remote access to EDGE SWITCH [1] dataexchange interfaces, management interfaces and feature activationinterfaces through the IP data path to the IP CARRIER NETWORK [6].

[0179] The TELEPHONE LINE INTERFACE [1.9] converts device-leveltelephone signals (e.g. POTS telephone signals) to/from digitallyencoded audio streams and digitally encoded device states (e.g.off-hook, on-hook, DTMF digits). The MEDIA STREAM CONTROLLER [1.7]interfaces the TELEPHONE LINE INTERFACE [1.9] and is responsible forrouting these media streams to/from the PACKETIZATION COPROCESSOR [1.6],performing media format transcoding (as required) by applying digitalsignal processing algorithms to them. Digital signal processingalgorithms run on the DIGITAL SIGNAL PROCESSOR [1.8]. The PACKETIZATIONCOPROCESSOR [1.6] takes responsibility for media stream transmissionthrough the IP ROUTING MODULE [1.2] using RTP.

[0180] The CENTRAL PROCESSING UNIT [1.10] is responsible for supervisingall network communications through the EDGE SWITCH [1], using the RANDOMACCESS MEMORY [1.11] to execute an operating system, networkcommunications protocol stacks, and CALL PROCESSING APPLICATIONS[1.23.2]. All of these software components are stored in a FILE SYSTEM[1.23] that uses the NON-VOLATILE MEMORY [1.12] as its storage medium.NON-VOLATILE MEMORY [1.12] is used to store a variety of databases,configuration files, and event histories.

Edge Switch Software Architecture

[0181]FIG. 6 depicts a software architecture for the EDGE SWITCH [1].The software components and subsystems shown should be viewed as controllogic to be layered over the EDGE SWITCH [1] hardware architecturedepicted in FIG. 5. Certain software elements serve as hardwareabstractions that maintain a direct control relationship over aparticular hardware subcomponent. Other software elements supportoperations that do not directly relate to any particular hardwaresubcomponent, but in fact impart higher functionality to the EDGE SWITCH[1] as a whole.

QoS IP Routing Functions

[0182] The NETWORK ADAPATION LAYER [1.13] represents programmable logic,firmware, or software subcomponents required to enable the BROADBANDNETWORK INTERFACE [1.1] to present IP connectivity to the IP ROUTINGMODULE [1.2] in OSI Layer 3. The NETWORK ADAPATION LAYER [1.13] isdesigned to be maintained as a discreet subsystem apart from the IPROUTING SYSTEM [1.14] so that it may be changed to support different OSILayer 2 technologies without requiring commensurate changes to the IPROUTING SYTEM [1.14].

[0183] The IP ROUTING SYSTEM [1.14] is the control software required toenable the IP ROUTING MODULE [1.2] to operate. This softwareincorporates the IP protocol stack and is responsible for supporting allIP routing functions for the EDGE SWITCH [1], including QoS arbitrationnecessary to support sharing transmission capacity between real-timevoice/video communications and common data transmission. Certainsoftware or firmware subcomponents of the IP ROUTING SYTEM [1.14] may beresponsible for packet labeling (or re-labeling), traffic shaping, flowcontrol, and other QoS arbitration functions related to managing IPpacket exchange between the IP ROUTING MODULE [1.2] and the routedterminal interfaces (i.e. COMPUTER DATA INTERFACE [1.4] and VIDEOSTREAMING DEVICE INTERFACE [1.5]).

[0184] Certain software or firmware subcomponents in of the IP ROUTINGSYSTEM [1.14] system may run on the IP ROUTING MODULE [1.2] (i.e.downloaded firmware or programmable logic) while others may run on theCENTRAL PROCESSING UNIT [1.10], communicating with the IP ROUTING MODULE[1.2] in a device control capacity.

[0185] The IP ROUTING SYSTEM [1.14] incorporates a software abstractionof the IP ROUTING MODULE [1.2], supporting internal APIs necessary toenable IP communications by the RTP PROTOCOL STACK [1.15], the SIPPROTOCOL STACK [1.16], the HTTP PROTOCOL STACK [1.17], and the SNMPPROTOCOL STACK [1.18]. Routing services such as Network AddressTranslation and programmable firewall features are also supportedthrough this abstraction.

Protocol Stacks for Network Communications

[0186] The RTP PROTOCOL STACK [1.15] runs primarily on the PACKETIZATIONCOPROCESSOR [1.6] so as to ensure consistently uninterrupted RTP mediatransmission through the network irrespective of the processing load onthe CENTRAL PROCESSING UNIT [1.10]. The RTP PROTOCOL STACK [1.15] isused by the ABSTRACT TELEPHONE CONTROLLER [1.19] to support real-timevoice communications by TELEPHONE STATIONS [3] plugged into theTELEPHONE LINE INTERFACE [1.19].

[0187] The SIP PROTOCOL STACK [1.16] runs on the CENTRAL PROCESSING UNIT[1.10] and is used by the ABSTRACT CALL MODEL [1.20] to support all SIPnetwork signaling operations. Among other roles, it functions as thedefault SIP Proxy Server for all voice and video terminals plugged intothe EDGE SWITCH [1], acting an intermediary for all SIP networksignaling operations between those terminal devices and those in thenetwork with whom they are communicating. FIG. 11 depicts this role ofthe SIP PROTOCOL STACK [1.16] to the extent that the DES as a systemfunctions as a distributed SIP Proxy Server, using the DNS SERVER [10]as a centralized database to translate E.164 dialing numbers into IPaddresses (as required to establish SIP call sessions in the ESN.

[0188] The HTTP PROTOCOL STACK [1.17] runs on the CENTRAL PROCESSINGUNIT [1.10] and is used to provide secure, session-based access to theXML MGMT INTERFACE [1.21] by remote management applications andnetwork-based applications. In a similar fashion, the SNMP PROTOCOLSTACK [1.18] also runs on the CENTRAL PROCESSING UNIT [1.10] andprovides a standards-based management interface to various DEVICE MGMTAGENT [1.22] and related data objects (i.e. SNMP Agents and SNMPManagement Information Blocks).

Terminal Interfaces

[0189] The COMPUTER DATA INTERFACE [1.4] and the VIDEO STREAMING DEVICEINTERFACE [1.5] are physical, routed interfaces to the IP ROUTING MODULE[1.2], thus control logic in the IP ROUTING SYSTEM [1.14] will modulateIP packet flows to/from COMPUTER WORKSTATIONS [5] and SET-TOP BOXES [4]plugged into these interfaces. TELEPHONE STATIONS [3] plugged into theTELEPHONE LINE INTERFACE [1.9] ultimately present themselves to the EDGESWITCH [1] software architecture through the ABSTRACT TELEPHONECONTROLLER [1.19], which provides an abstract software control model forthe MEDIA STREAM CONTROLLER [1.7] and the TELEPHONE LINE INTERFACE[1.9]. Logical media stream control operations, adjunct digital signalprocessing functions, and device-level control of TELEPHONE STATIONS [3]are made accessible to other internal EDGE SWITCH [1] softwaresubcomponents through an API presented by the ABSTRACT TELEPHONECONTROLLER [1.19]. This API contains functions that enable the detectionof device-level telephone signaling events (i.e. on-hook, off-hook,flash, DTMF digits, flash) originating from the TELEPHONE STATIONS [3]plugged into the TELEPHONE LINE INTERFACE [1.9]. These logicaloperations and functions supported by the API are realized by mappingthem to physical operations supported by the MEDIA STREAM CONTROLLER[1.7] and the TELEPHONE LINE INTERFACE [1.9];

[0190] SET-TOP BOXES [4] are native SIP network signaling endpoints(i.e. contain a SIP User Agent) and perform SIP network signalingthrough the SIP PROTOCOL STACK [1.16], employing it as their default SIPProxy Server. TELEPHONE STATIONS [3] are represented as SIP networksignaling endpoints by a SIP User Agent function provided by theABSTRACT CALL MODEL [1.20]. Thus, both terminal types present themselvesas SIP network signaling endpoints registered with the SIP PROTOCOLSTACK [1.16] (functioning as a SIP Proxy Server). As a result, SIPnetwork signaling events from either type of terminal can be interceptedand used to trigger CALL PROCESSING APPLICATIONS [1.23.2].

Terminal Control and Call Processing

[0191] The ABSRACT CALL MODEL [1.20] provides an abstract endpointrepresentation for all TELEPHONE STATIONS [3] and SET-TOP BOXES [4]plugged into the EDGE SWITCH [1]. The SIP PROTOCOL STACK [1.16] and theABSTRACT TELEPHONE CONTROLLER [1.19] present network signaling eventsand TELEPHONE STATION [3] device-level signaling events, respectively,to the ABSTRACT CALL MODEL [1.20]. Either type of signaling event maytrigger execution of CALL PROCESSING APPLICATIONS [1.23.2] stored in theFILE SYSTEM [1.23]. CALL PROCESSING APPLICATIONS [1.23.2] can performnetwork signaling operations (such as call control) through the SIPPROTOCOL STACK [1.16] or perform media control and device-levelTELEPHONE STATION [3] control operations through the ABSTRACT TELEPHONECONTROLLER [1.19].

[0192]FIG. 7 depicts architectural details related to the design andoperation of the EDGE SWITCH [1] call model. The DEFINITIONS sectionentry for the ABTRACT CALL MODEL [1.120] provides an expanded discussionof terminal control and call processing as it relates to thearchitectural context set forth in FIG. 7.

Management Interfaces

[0193] The XML MGMT INTERFACE [1.21] provides a means by which a clientapplication may: (a) remotely access information stored within FILESYSTEM [1.23] databases; (b) remotely invoke EDGE SWITCH [1] telephonecontrol and call processing features; and/or (c) remotely invoke DEVICEMGMT AGENTS [1.22] resident on the EDGE SWITCH [1]. A remote client willestablish an HTTP session through the HTTP PROTOCOL STACK [1.17]. Remoteclient access for the purpose of data exchange or remote invocation offeatures is based on using XML-encoding for all information. Datastructures and parameter lists passed between the client and the EDGESWITCH [1] during remote access are all XML-encoded.

[0194] The SNMP PROTOCOL STACK [1.18] provides a standards-based devicemanagement interface similar to that provided by the combination of theHTTP PROTOCOL STACK [1.17] and the XML MGMT INTERFACE [1.21]. However,the transactions occurring through this interface are initiated by aremote network management station compliant with SNMP. The DEVICE MGMTAGENTS [1.22] in the EDGE SWITCH [1] include specialized “SNMP Agents”that communicate with the network management station using ManagementInformation Blocks (MIBS). Thus, the SNMP PROTOCOL STACK [1.18]implements a more formal presentation of network element managementfunctions to the IP CARRIER NETWORK [6], as would be required forimplementation of the ESN by a carrier.

Distributed Edge Switch Carrier Network Reference Architecture

[0195]FIG. 8 depicts a DES carrier network reference architecture. Itprovides a formal presentation of network elements that define the ESNand is used by subsequent discussions within this disclosure to providean operational context for system management, call signaling, andnetwork service delivery workflow sequences. All network elements aredescribed in significantly more detail in the DEFINITIONS section.

[0196] The ESN recognizes the PSTN as an important “companion network”with which the ESN must fully interoperate. The ESN must support callsessions that have one endpoint in the ESN and another in the PSTN,whether for the purpose of point-to-point communication betweenTELEPHONE STATIONS [3] or for access to NETWORK-BASED ENHANCED SERVICES[18] deployed in the PSTN.

[0197]FIG. 8 depicts important ESN network elements that are considerednecessary to support the full breadth of system management, callsignaling, and network service delivery capabilities of the DES. WhereasFIG. 8 provides the architectural context for all operations supportedby the DES, FIGS. 9, 10 & 11 will selectively expose only those networkelements from FIG. 8 that are required to illustrate particular workflowsequences.

Distributed Edge Switch System Management Workflow

[0198]FIG. 9 depicts selected elements of the DES carrier networkreference architecture for the purpose of illustrating DES systemmanagement workflow sequences. FIG. 9 introduces selected carrieroperations support system (OSS) elements for the purpose ofdemonstrating how the DES, from an operational perspective, integrateswith existing carrier back-office infrastructure.

[0199] The DES system management model does not use IP addresses as ameans to identify endusers of network services. It assumes that IPaddress assignments are dynamic, transient, and easily manipulated byusers. Instead, all subscriber transactions that must be accounted forin event histories (i.e. billing records) are tracked on the basis ofthe unique physical device address of the EDGE SWITCH [1] that generatedthe event. The physical device address of the EDGE SWITCH [1] is notaccessible to the user, cannot be modified, and is passed through thenetwork in encrypted format, thus it cannot be altered, falsified, orotherwise easily misrepresented.

[0200] The DES system management workflow sequences below reference theten programmatic relationships shown in FIG. 9. These workflow sequencesdo not capture the full extent of DES system management, but insteadhighlight important examples.

Edge Switch Synchronization with SMP

[0201] In the event of EDGE SWITCH [1] replacement, the SYSTEMMANAGEMENT PLATFORM [2] is required to be able to reconstruct thesoftware load and operating configuration (including allsubscriber-specific information) used by a particular EDGE SWITCH [1].Also, any changes made by end user (the subscriber) to Class of Servicesettings or service delivery preferences must be reflected back into theSYSTEM MANAGEMENT PLATFORM [2] (and vice-versa) through asynchronization process. The synchronization process is initiatedautomatically through {1} by either the EDGE SWITCH [1] or the SYSTEMMANAGEMENT PLATFORM [2], whenever one or the other detects that it hasexperienced a change in operating configuration and/orsubscriber-specific information that is understood to be maintained byboth entities.

[0202] Not every data object on the EDGE SWITCH [1] is necessarilymaintained on the SYSTEM MANAGEMENT PLATFORM [2]. For example, longafter being reported to the SYSTEM MANAGEMENT PLATFORM [2] for servicebilling purposes, potentially years of call log data could be retainedwithin the EVENT RECORD REPOSITORY [1.23.1], remaining accessible tointeractive calling services. In the unexpected event of EDGE SWITCH [1]replacement, this call log information would no longer be accessible tothe subscriber (without the carrier extracting it using specialdiagnostic tools in a service depot). Presumably, they would have savedcall log reports by other means if the information was consideredimportant to them.

[0203] The EDGE SWITCH [1] synchronization process is presented for acircumstance of replacement—a situation in which the entire contents ofthe EDGE SWITCH [1] must be updated. However, the synchronizationprocess is optimized to ensure that only new or changed information issynchronized. Thus, synchronization is a general process of informationmanagement that will be invoked following many types of operations, suchas whenever a subscriber changes their Class of Service settings orpersonal preferences. The synchronization process may be executed inbatch mode, whereby a certain number of changes trigger execution, orperhaps it occurs only at certain times of the day, depending on howcritical the information. Truly critical changes in information, such aschanges in Class of Service, are originated on the SYSTEM MANAGMENTPLATFORM [2] first to ensure it is retained in the event ofsynchronization failure.

Edge Switch Reporting of Billable Events to OSS

[0204] In the ESN, the EDGE SWITCH [1] originates billable events andstores them locally until a pre-programmed threshold is met, at whichtime it reports them to the NETWORK BILLING SYSTEM [17]. When an EDGESWITCH [1] detects the threshold is met, it initiates a transmission ofnew billable events to the SYSTEM MANAGEMENT PLATFORM [2] via {1}. TheSYSTEM MANAGEMENT PLATFORM [2] confirms receipt of these events.

[0205] Each event is bound to a particular network subscriber based uponthe physical device address of the EDGE SWITCH [1] that originated it.The SYSTEM MANAGEMENT PLATFORM [2] sorts and reformats the billableevents into standard-format billing records prior to transmitting themto the NETWORK BILLING SYSTEM [17] via {10}.

Edge Switch Service Delivery Monitoring by OSS

[0206] The SYSTEM MANAGEMENT PLATFORM [2] actively monitors servicedelivery by the EDGE SWITCHES [1] and reports their status to theNETWORK OPERATIONS CENTER [16]. Each EDGE SWITCH [1] is programmed toreport its status to the SYSTEM MANAGEMENT PLATFORM [2] at a specific,pre-determined time interval. When an EDGE SWITCH [1] detects that thetime interval has expired, or at any time when it detects an errorcondition, it initiates a transmission of a status report to the SYSTEMMANAGEMENT PLATFORM [2] via {1}. The SYSTEM MANAGEMENT PLATFORM [2]confirms receipt of this report and the EDGE SWITCH [1] resets itstimer. The SYSTEM MANAGEMENT PLATFORM [2] then prioritizes, sorts andreformats these reports into a standard format prior to transmittingthem to the NETWORK OPERATIONS CENTER [17] via {9}.

[0207] If an EDGE SWITCH [1] report shows an alarm condition, or if theEDGE SWITCH [1] fails to report within a specific time frame, the SYSTEMMANAGEMENT PLATFORM [2] will expedite reporting of this information tothe NETWORK OPERATIONS CENTER [16] as an alarm condition that requiresexpedited remediation.

Edge Switch Troubleshooting by OSS

[0208] At any time, the NETWORK OPERATIONS CENTER [16] may query aparticular EDGE SWITCH [1] (or defined group of EDGE SWITCHES [1]) togenerate an updated status report and/or to initiate one or moreinternal diagnostic programs (e.g. DEVICE MGMT AGENTS [1.22]) residenton the EDGE SWITCH [1] for the purpose of remote troubleshooting. TheNETWORK OPERATIONS CENTER [16] may also retrieve, view, and/or modify aparticular EDGE SWITCH [1] base configuration and allsubscriber-specific information stored on it.

[0209] All of these interactions between the NETWORK OPERATIONS CENTER[16] and one or more EDGE SWITCHES [1] occur through the same generalmechanism: the NETWORK OPERATIONS CENTER [16] first defines a selectpopulation of subscribers based on appropriate criteria such as: (a) thenames or dialing numbers of one or more individual subscribers; (b) thename of a group of subscribers (e.g. an organization such as abusiness); or (c) a group of subscribers within a geographical region.The definition of a select population occurs though interactions betweenthe NETWORK OPERATIONS CENTER [16] and the SYSTEM MANAGEMENT PLATFORM[2] via {9}. Through a similar mechanism, the NETWORK OPERATIONS CENTER[16] then selects the desired logical troubleshooting operations to beapplied to this select population.

[0210] The SYSTEM MANAGEMENT PLATFORM [2] translates the selectpopulation of subscribers into a population of physical EDGE SWITCHES[1] that are providing network services to those subscribers. It nexttranslates the logical troubleshooting operations to be applied to thisselect subscriber population into sequences of EDGE SWITCH [1]management operations. These EDGE SWITCH [1] management operations arethen executed as interactions between the SYSTEM MANAGEMENT PLATFORM [2]and the EDGE SWITCHES [1] via {1}.

[0211] The EDGE SWITCHES [1], for their part, execute the devicemanagement operations and transmit reports to the SYSTEM MANAGEMENTPLATFORM [2] via {1}. The SYSTEM MANAGEMENT PLATFORM [2] confirmsreceipt of these reports, sorts and reformats them into a standardformat prior to transmitting them to the NETWORK OPERATIONS CENTER [17]via {9}.

Edge Switch Provisioning and Configuration by OSS

[0212] The NETWORK PROVISIONING SYTEM [15] must initiate at least threemajor operations to prepare the ESN for network service delivery to aselect population of one or more subscribers:

[0213] (a) Update carrier policies to enable network service delivery tothis select population of subscribers;

[0214] (b) Configure the network dialing plan to include terminals usedby the select population of subscribers.

[0215] (c) Configure DES to provide network services to this selectpopulation of subscribers in a manner that is consistent with carrierpolicies.

[0216] Carrier policies are updated by existing means via {7}. Thelogical provisioning operations typically include initially adding theselect population of subscribers to the POLICY SERVER [14] and assigninga default Class of Service. In addition, each subscriber is assigned oneor more dialing numbers (or other logical endpoint addresses accordingto naming conventions used to identify subscriber voice and multimediaterminals). In the ESN, the dialing plan for the most part is maintainedby the DNS SERVER [10]; thus the NETWORK PROVISIONING SYSTEM [15] mustensure that dialing numbers and/or endpoint addresses assigned to theselect subscriber population in the POLICY SERVER [14] are alsorepresented within the carrier's DNS infrastructure. The NETWORKPROVISIONING SYSTEM [15] updates the DNS SERVER [10] via {6}.

[0217] The NETWORK PROVISIONING SYSTEM [15] configures the DES toprovide network services to a select population of subscribers throughits interactions with the SYSTEM MANAGMENT PLATFORM [2] via {8}: theNETWORK PROVISIONING SYSTEM [15] first defines a select population ofsubscribers based on appropriate criteria such as: (a) the names ordialing numbers of one or more individual subscribers; (b) the name of agroup of subscribers (e.g. an organization such as a business); or (c) agroup of subscribers within a geographical region. The definition of aselect population occurs though interactions between the NETWORKPROVISIONING SYSTEM [15] and the SYSTEM MANAGEMENT PLATFORM [2] via {8}.Through a similar mechanism, the NETWORK PROVISIONING SYSTEM [15] theninitiates automatic provisioning for that select population.

[0218] The SYSTEM MANAGEMENT PLATFORM [2] initiates automaticprovisioning by synchronizing all of its internal administrativeinformation for the select population with the same select population onthe POLICY SERVER [10] via {5}. If there are determined to be members ofthe select population that exist on the POLICY SERVER [10] but that donot exist within the SYSTEM MANAGEMENT PLATFORM'S [2] internaladministrative information, then these members are identified as “newsubscribers;” new accounts are then created on the SYSTEM MANAGEMENTPLATFORM [2]. The Class of Service capabilities in the POLICY SERVER[10] for all members of the select population are translated intoappropriate DES Class of Service representations (to the extentpossible) for the corresponding select population on the SYSTEMMANAGMENT PLATFORM [2]. New subscribers are assigned default Class ofService settings and default service preferences.

[0219] Each subscriber account maintained on the SYSTEM MANAGEMENTPLATFORM [2] contains a registry used to associate that subscriber withone or more physical EDGE SWITCHES [1], each identified by a uniquephysical device address. Each registered EDGE SWITCH [1] has itsphysical location (street address) listed along with the dialing numbersit serves. Conceptually, each EDGE SWITCH [1] is serving a portion ofthe overall network dialing plan.

[0220] Having synchronized its internal administrative information withthe POLICY SERVER [10], the SYSTEM MANAGMENT PLATFORM [2] thentranslates the select population of subscribers into a population ofregistered EDGE SWITCHES [1] that are providing network services tothose subscribers. It next attempts to communicate with each EDGE SWITCH[1] via {1} to upload the necessary system software andsubscriber-specific information necessary to support network servicedelivery by the EDGE SWITCH [1]. Subscriber-specific informationincludes a specific set of Class of Service capabilities purchased bythe subscriber. Class of Service capabilities are accompanied by defaultClass of Service settings. Some settings are assigned default networkservice delivery preferences as appropriate to the particular networkservice effected.

[0221] The EDGE SWITCHES [1], for their part, confirm the success orfailure of the provisioning operations, each transmitting a report tothe SYSTEM MANAGEMENT PLATFORM [2] via {1}. When the SYSTEM MANAGEMENTPLATFORM [2] has completed provisioning and configuring all EDGESWITCHES [1] for the select population, it sorts the reports returned bythe EDGE SWITCHES [1] and reformats them into a standard format prior totransmitting them to the NETWORK PROVISIONING SYSTEM [15] via {8}. Aspart of the provisioning process, the EDGE SWITCHES [1] in the selectpopulation automatically perform a reset and come online to beginnetwork service delivery; they then begin to transmit periodic statusreports as described by the workflow sequence “Edge Switch ServiceDelivery Monitoring by OSS.”

End-user Configuration of Edge Switch

[0222] An end-user (i.e. the subscriber) may performapplication-mediated configuration operations that enable them to viewand modify EDGE SWITCH [1] Class of Service settings and network servicedelivery preferences using a web browser. An EDGE SWITCH [1]configuration and network services management web application running ona WEB SERVER [11] presents a graphical user interface via {2}, exposinginformation relevant to that particular subscriber's Class of Service.The web application performs a secure log-in via {3} to the XML MGMTINTERFACE [1.21], within the context of an HTTP session supportedthrough the HTTP PROTOCOL STACK [1.17].

[0223] Communications between the web application and the EDGE SWITCH[1] may be encrypted to ensure secure access. End-user modifications tothe EDGE SWITCH [1] configuration or subscriber-specific information arereflected back to the SYSTEM MANAGEMENT PLATFORM [2] as soon as it ispractical to do so, according to the workflow sequence “Edge SwitchSynchronization with SMP.”

End-User Interaction with Edge Switch

[0224] An end-user (i.e. the subscriber) may performapplication-mediated interactions with the EDGE SWITCH [1] as an adjunctto network service delivery. Certain network services (or elements ofnetwork services), such as interactive calling services are implementedas web applications running on a WEB SERVER [11]. The web applicationpresents a graphical user interface via {2}, exposing informationrelevant to that particular network service, such as display of call logdata, for example.

[0225] The web application performs a secure log-in via {3} to the XMLMGMT INTERFACE [1.21], within the context of an HTTP session supportedthrough the HTTP PROTOCOL STACK [1.17]. Communications between the webapplication and the EDGE SWITCH [1] may be encrypted to ensure secureaccess. Through the XML MGMT INTERFACE [1.21], the web application may(a) access information stored in various EDGE SWITCH [1] databases,and/or (b) access features and functions supported by the EDGE SWITCH[1], such as call control operations.

Distributed Edge Switch Call Signaling Workflow

[0226]FIG. 10 depicts selected elements of the DES carrier networkreference architecture for the purpose of illustrating DES network callsignaling workflow sequences. SIP network signaling paths and databasequeries are shown as they relate to various call set-up examples. RTPbearer paths are not shown and should be assumed from a logicalperspective to occur point-to-point between SIP network signalingendpoints participating in a SIP call session.

Role of Distributed Edge Switch as a Distributed SIP Proxy Server

[0227]FIG. 11 is a companion to FIG. 10, providing details as to how theDES functions as a distributed SIP Proxy Server. In the DES, each EDGESWITCH [1] embeds its own SIP Proxy Server within the SIP PROTOCOL STACK[1.16]. This SIP Proxy Server replaces most of the SIP Proxy Serverfunctionality that is in the NGN provided by a centralized,network-based SIP Proxy Server, such as the SIP PROXY SERVER [12]depicted in FIG. 8 for the Distributed Edge Switch Carrier ReferenceNetwork Architecture. The SIP Proxy Server within the SIP PROTOCOL STACK[1.16] has access to subscriber policy information (e.g. subscriberClass of Service and preferences) stored internally within the EDGESWITCH [1]; thus in most cases it does not need to defer to anetwork-based SIP PROXY SERVER [12] to make policy-related decisions onits behalf. In addition, the The SIP Proxy Server within the SIPPROTOCOL STACK [1.16] may access the DNS SERVER [10] through theBROADBAND ACCESS NETWORK [6.1] in order to translate dialing numbers toIP addresses. Summarily, the centralized SIP PROXY SERVER [12] is forthe most part not used by the DES (or in any ESN) to support SIP callsessions between EDGE SWITCHES [1].

[0228] It is likely the case that a carrier will not allow unrestrictedSIP connectivity within the IP CARRIER NETWORK [6]. To control access tocarrier-owned SIP network signaling endpoints (e.g. EDGE SWITCHES [1],PSTN GATEWAYS [8], SIP APPLICATION SERVERS [13]), certain SIP callsessions may be encrypted or contain specialized parameters. To thisend, the SIP PROTOCOL STACK [1.16] provides a “protocol grooming”function to, if necessary, re-write, encode, and/or decode SIP messagesfor the purpose of ensuring secure, syntactically correct SIP networksignaling within the IP CARRIER NETWORK [6].

[0229] Internally within the EDGE SWITCH [1], TELEPHONE STATIONS [3]plugged into it are represented as SIP User Agent instances by theABSTRACT CALL MODEL'S [1.20] Telephone Gateway function. These SIP UserAgents are created to operate on behalf of TELEPHONE STATIONS [3] thatare by themselves incapable of performing SIP network signalingoperations. These SIP User Agents must utilize the SIP PROTOCOL STACK[1.16] as their default SIP Proxy Server in order to participate in SIPnetwork signaling operations that involve carrier-owned SIP networksignaling endpoints. SET-TOP BOXES [4] are native SIP network signalingendpoints, and when plugged into the EDGE SWITCH [1], they too mustspecify the SIP PROTOCOL STACK [1.16] as their default SIP Proxy Serverin order to participate in SIP network signaling operations that involvecarrier-owned SIP network signaling endpoints.

[0230] Because each EDGE SWITCH [1] contains its own SIP Proxy Server,the network's capacity to provide secure SIP Proxy services scales withthe network itself. Each EDGE SWITCH [1] contains the computingresources necessary to provide SIP proxy services to all terminalsplugged into it. The DEFINITIONS section of this disclosure contains afull discussion of the EDGE SWITCH [1] call model, and here it isexplained how the SIP Proxy Server capability of the SIP PROTOCOL STACK[1.16] makes possible the implementation of the ABSTRACT CALL MODEL'S[1.20] Calling Service Delivery Function and Admission Control Function.Both of these functions operate in the network signaling plane and aremade possible as a result of the fact that the SIP PROTOCOL STACK [1.16]is playing the role of intermediary in all calls originated from andanswered by the EDGE SWITCH [1].

[0231] Unique to the DES is its peer-to-peer call routing and“multi-tiered” configurable call set-up model that together: (a) enablethe largest number of simultaneous calls to occur with the lowestpossible utilization of network resources, and (b) guarantee virtuallyinstantaneous call set-up times for on-network calls. These designelements benefit the carrier implementing the DES because it enablesthem to deliver an end-user experience that significantly improves uponwhat is possible through the legacy PSTN or the proposed NGN:

[0232] DES on-network call set-up times are virtually instantaneous,generating ring signaling and two-way voice communications without anyperceivable delay.

[0233] For all practical intents and purposes, DES on-network callset-up will virtually never block due to trunk congestion (i.e. will notreturn “network busy”);

[0234] DES feature delivery (e.g. office telephone features, access tonetwork-based applications) to the end-user through voice and multimediaterminals is virtually instantaneous.

[0235] The multi-phase call set-up model supported by the EDGE SWITCH[1] may be configured to optimally support call routing requirementsunique to a specific carrier's implementation of the ESN. The servicelogic needed to supervise the EDGE SWITCH [1] call set-up procedure isimplemented in a CALL PROCESSING APPLICATION [1.23.2]. In the case ofcall origination by the EDGE SWITCH [1], a CALL PROCESSING APPLICATION[1.23.2], for example, would be triggered to execute when an off-hookevent was detected for a TELEPHONE STATION [3] plugged into it.

[0236] Since all network service delivery and call processing logic ismanaged internally by the EDGE SWITCH [1] and since billing events (i.e.call accounting records) are stored internally by the EDGE SWITCH [1],the greater or lesser involvement of centralized network resources hasno impact on the ability of the EDGE SWITCH [1] to (a) deliver basiccalling services according to the subscriber's Class or Service, and/or(b) to account for their use through the EDGE SWITCH'S [1] internalorigination, storage, and forwarding of billable event records to theSYSTEM MANAGEMENT PLATFORM [2]. Consequently, call routing algorithmsare not required to route calls through centralized SIP PROXY SERVERS[12] that are responsible for originating billable events and thus canbe optimized with greater flexibility. FIG. 10 depicts the ESNarchitectural context necessary to describe selected call signalingworkflow examples that illustrate this flexibility:

On-switch Call

[0237] An on-switch call occurs when a TELEPHONE STATION [3] or SET-TOPBOX [4] plugged into the EDGE SWITCH [1] attempts to call anotherTELEPHONE STATION [3] or SET-TOP BOX [4] plugged into the same EDGESWITCH [1]. As depicted in FIG. 10 for the EDGE SWITCH [1] labeled B,SIP call signaling occurs internally through the SIP PROTOCOL STACK[1.71], essentially point-to-point between internal SIP User Agents asindicated by {1}. RTP bearer transmission occurs point-to-point throughthe IP ROUTING MODULE [1.2] in much the same way. As an alternative toRTP transmission, an on-switch call may simply interconnect mediastreams associated with the participating TELEPHONE STATIONS [3]directly through the MEDIA STREAM CONTROLLER [1.7].

[0238] If the dialing number for the far-end cannot be identified as aTELEPHONE STATION [3] or SET-TOP BOX [4] plugged into the same EDGESWITCH [1], call set-up service logic may choose to initiate a directcall or and indirect call, depending the circumstance. Most calls in theDES are initiated as direct calls.

Direct Call

[0239] A direct call occurs when a TELEPHONE STATION [3] or SET-TOP BOX[4] calls another TELEPHONE STATION [3] or SET-TOP BOX [4] that is notplugged into the same EDGE SWITCH [1] and without using an intermediate,centrally-located SIP PROXY SERVER [10] in the IP CARRIER NETWORK [6].As depicted in FIG. 10 for the EDGE SWITCH [1] labeled A (originatingthe call in this case), SIP call signaling occurs directly to the EDGESWITCH [1] labeled B (as indicated by {3}). In this case, the SIP ProxyServer capability of the SIP PROTOCOL STACK [1.16], as depicted in FIG.11, is able to perform a DNS SERVER [2] look-up to convert the far-enddialing number to an IP endpoint address as indicated by {2}. Thus, theSIP PROTOCOL STACK [1.16] within the EDGE SWITCH [1] is fully capable ofperforming all operations necessary to establish a SIP call sessionbased on E.164 dialing number addressing without assistance from acentrally-located SIP PROXY SERVER [10]. Class of Service informationthat would determine whether or not a subscriber should be allowed toplace the call in the first place is all stored internally by the EDGESWITCH [1] and updated as required by the SYSTEM MANGEMENT PLATFORM [2].As a result, there is no need for the SIP PROTOCOL STACK [1] to querythe POLICY SERVER [10] for additional information necessary to set-upthe call. RTP bearer transmission occurs point-to-point through the IPCARRIER NETWORK [6] in the usual way for SIP call sessions.

Indirect Call

[0240] An indirect call occurs when a TELEPHONE STATION [3] or SET-TOPBOX [4] uses an intermediate SIP PROXY SERVER [10] to call anotherTELEPHONE STATION [3] or SET-TOP BOX [4]. This type of call occurs whenthe service logic used to set-up the call explicitly uses the IP address(or name) of the network-based SIP PROXY SERVER [10] as the SIP ProxyServer that should set-up the call.

[0241] As depicted in FIG. 10 for the EDGE SWITCH [1] labeled A(originating the call in this case), SIP call signaling occurs throughthe SIP PROXY SERVER [12], as indicated by {4}. The SIP PROXY SERVER[12] will access the POLICY SERVER [14] for network call routinginformation, as indicated by {5}, and a DNS SERVER [2] to convert thefar-end dialing number to an IP endpoint address, as indicated by {6}.The SIP PROXY SERVER [12] then functions as a SIP message router toshuttle SIP network signaling to and from the far-end EDGE SWITCH [1]labeled B, as indicated by {7}. RTP bearer transmission occurspoint-to-point through the IP CARRIER NETWORK [6].

[0242] In the DES, this type of indirect call usually occurs when thedialed number is an endpoint that can only be reached through a PSTNGATEWAY [8], or when the dialed number is a SIP APPLICATION SERVER [13],as indicated by {8} and {9}. In these cases, the carrier will oftendeploy a SIP PROXY SERVER [10] as a means to implement a load-balancingfunction; that is, the carrier will configure the SIP PROXY SERVER [10]to route large numbers of incoming calls to an available PSTN GATEWAY[8] or SIP APPLICATION SERVER [13]. In the reverse direction, incomingcalls from the PSTN GATEWAY [8] to EDGE SWITCHES [1], for example, mustbe routed through the SIP PROXY SERVER [10] so that it can be directedto the correct EDGE SWITCH [1] in the IP CARRIER NETWORK [6].

On-network and Off-network Calls

[0243] All direct or indirect SIP call sessions that occur betweenendpoints that lie within the ESN (i.e. entirely within the IP CARRIERNETWORK [6]), end-to-end, are termed “on-network” calls. An“off-network” call occurs whenever one end of a call session is anendpoint that lies outside of the IP CARRIER NETWORK [6] (such as thePSTN [7]), regardless of which endpoint originated the call.

[0244] Off-network calls to the PSTN [7] utilize a PTSN GATEWAY [8] tocomplete the call path for both signaling and bearer connections.Because the PSTN GATEWAY [8] is a shared resource, potentially locatedonly in selected network segments and accessed by many network users atthe same time, it requires some degree of expanded access control. Thecarrier may wish to partition the IP CARRIER NETWORK [6] with respect toPSTN GATEWAY [8] access, perhaps for the purposes of load balancing andensuring redundancy. The PSTN GATEWAY [8] will require assistance inrouting calls inbound from the PSTN [7] to specific IP CARRIER NETWORK[6] endpoints. For all these purposes, a SIP PROXY SERVER [12] is mostoften used as an intermediary; thus as a practical matter, anoff-network call is virtually always an indirect call. An example of anoff-network call is depicted in FIG. 10 where the EDGE SWITCH [1]labeled A connects to a PSTN [7] endpoint through the PSTN GATEWAY [8],as indicated by {10} and {11}.

Distributed Edge Switch Network Service Delivery Workflow

[0245]FIG. 12 depicts selected elements of the DES carrier networkreference architecture for the purpose of illustrating DES networkservice delivery workflow sequences. According to the DES networkservice delivery model, services internal to the EDGE SWITCH [1] andthose residing in the network are combined into more comprehensivenetwork services based on the subscriber's Class of Service. Almostevery network service provided by the EDGE SWITCH [1] is derived from,initiated by, or built on top of EDGE SWITCH BASIC FEATURES [1.24]. EDGESWITCH BASIC FEATURES [1.24] render TELEPHONE STATION FEATURES andSET-TOP BOX FEATURES to subscribers through TELEPHONE STATIONS [3] andSET-TOP BOXES [4] respectively, as indicated by {1}.

[0246] Any call originated or received by a terminal plugged into theEDGE SWITCH [1] will the trigger the execution of particular servicelogic (i.e. CALL PROCESSING APPLICATIONS [1.23.2]). The execution ofwhich particular service logic depends upon the subscriber's Class ofService capabilities, settings, and preferences; some settings willchange the logic to a completely different type of service logicaltogether whereas other settings may simply alter some aspect of theservice logic. In some cases, the service logic of EDGE SWITCH BASICFEATURES [1.24], such as “call-forwarding” for example, may as a matterof course redirect calls to NETWORK-BASED ENHANCED SERVICES [18].NETWORK-BASED ENHANCED SERVICES [18] may be accessible to the EDGESWITCH [1] as network signaling endpoints residing in either the PSTN[7], as indicated by {4}, or the IP CARRIER NETWORK [6], as indicated by{5}.

[0247] An ready example of {5} exists in a popular network servicecalled “voice call-answering.” To implement voice call-answering, Aconditional call-forwarding feature (EDGE SWITCH BASIC FEATURE [1.24])is programmed to forward a call to a voice call-answering application(NETWORK-BASED ENHANCED SERVICE [18]) if the TELEPHONE STATION [3] ringsthree times without being answered or is busy.

[0248] An EDGE SWITCH BASIC FEATURE [1.24] may be substituted with EDGESWITCH OVERRIDE FEATURE [1.25] that either (a) adds functionality to ontop of it, as indicated by {3} or (b) provides an alternativeimplementation of it, as indicted by {2}.

[0249] To provide an example of {3} (i.e. adds functionality to EDGESWITCH BASIC FEATURE [1.24]) the previous example of voicecall-answering can be expanded to offer a Class of Service setting thatwould send an instant message to inform the subscriber that they werereceiving a voice message. In this case, a simple instant messagingclient in the EDGE SWITCH [1] would perform the messaging operationafter the caller was forwarded to the voice call-answering application.The original functionality of basic call-answering remains unchanged.

[0250] To provide an example of {2} (i.e. provides an alternativeimplementation of an EDGE SWITCH BASIC FEATURE [1.24]) the basiccall-forwarding function could be replaced completely with a moreadvanced version that maintained a “do-not-disturb” function based ontime of day. At certain times of the day (as programmed by thesubscriber) all callers would be automatically transferred to the voicecall-answering application and the telephone would not ring. Theoriginal functionality of basic call-answering is changed to alter itsbehavior based on the time of day.

[0251] In some cases, the desired EDGE SWITCH OVERRIDE FEATURE [1.25] istoo complex for the EDGE SWITCH [1] to implement internally. Asindicated by {6}, the EDGE SWITCH BASIC FEATURE [1.24] is replaced witha NETWORK-BASED OVERRIDE FEATURE [19]. An example of {6} would be a“contact dialing” feature in which the standard dial-tone provided as anEDGE SWITCH BASIC FEATURES [1.24] is completely replaced with replacedwith a NETWORK-BASED OVERRIDE FEATURE [19] that supports multipledialing modalities depending on subscriber whim. The new dial-tonefeature would interoperate with the subscribers contact list, enablingthem to “click to dial” from the COMPUTER WORKSTATION [5] desktop, orsimply speak the name of the contact they wish to dial, or allow them todial the telephone in the usual manner.

Preferred Embodiment of Edge Switch

[0252]FIG. 13 depicts a preferred embodiment for the DES. A version ofthe EDGE SWITCH [1] has been constructed for residential subscriberdeployment using a Very-high-data-rate Digital Subscriber Line (VDSL)interface to the BROADBAND ACCESS NETWORK [6.1]. VDSL bit transfer ratesvary according to cable length and by manufacturer. VDSL chip-setscurrently available support downstream bit transfer rates over 25megabits/second for cable lengths in excess of 3,500 feet. Upstream bittransfer rates are typically lower than downstream rates.

Edge Switch Physical Form Factor

[0253] The EDGE SWITCH [1] supports four individual POTS lines and fourSET-TOP BOXES [4] using an ETHERNET SWITCH [20] plugged into the VIDEOSTREAMING DEVICE INTERFACE [1.5]. 10Base-T ethernet technology is usedfor the cable connections. An ETHERNET HUB [9] plugged into the COMPUTERDATA INTERFACE [1.4] also uses 10Base-T ethernet technology. TheETHERNET HUB [9] enables four COMPUTER WORKSTATIONS [5] to share asingle data service.

[0254] The EDGE SWITCH [1] is deployed on the network-side of theSUBSCRIBER NETWORK INTERFACE [21] at the Telco Entrance Facility wherethe inside wiring is accessible through a POTS channel bank mounted onthe outside of the subscriber premise. It is powered by current from thecopper wire plant supporting the VDSL broadband network service.

[0255] EDGE SWITCH [1] electronics and connectors are contained withinan environmentally protected plastic housing that incorporates a hingedcover panel used to provide service access. The physical dimensions ofthe plastic housing mirror the form factor of the Telco EntranceFacility (10″ height×9″ width×3″ depth). Using the existing TelcoEntrance Facility (originally used for POTS service), the EDGE SWITCH[1] gains the electrical and environment protection provided for theexisting entrance device; additional protection capabilities within thehousing are incorporated in the design to further protect the electroniccomponents.

Bandwidth Utilization

[0256] Each of the four POTS interfaces support three-way callingfeatures accessible to the TELEPHONE STATIONS [3]. Internally, theysupport four-way calling so as to enable an additional call leg in athree-way call as would occur if the call was to be intercepted for lawenforcement assistance. Voice communications nominally utilize theG.729a codec (vocoder type), which consumes 8 kilobytes/second per voicebearer channel (media stream) connection. With four simultaneous POTSsessions, each involved in three-way intercepted call, the totalbandwidth consumed for voice transmission is approximately 100kilobits/second (not including signaling and packetization overhead). Inthe event that the EDGE SWITCH [1] detects modem tones on a line, suchas from a fax machine, it will automatically change the codec from G.729a to G.711 so as to enable modem-based data communications over thevoice bearer channel.

[0257] A high-quality video stream consumes approximately 3.5megabits/second; thus total bandwidth for four simultaneous video(multimedia) is approximately 14 megabits/second. Taking these estimatesinto consideration, the maximum bandwidth that could be consumed by EDGESWITCH [1] voice and multimedia sessions is approximately 15megabits/second. Assuming a VDSL broadband capable of supporting 20megabits/second, at least 5 megabits/second would be available for datacommunications by the COMPUTER WORKSTATIONS [5].

Operational Capacity

[0258] The EDGE SWITCH [1] supports EDGE SWITCH BASIC FEATURES [1.24]for TELEPHONE STATIONS [1], SET-TOP BOXES [4] and COMPUTER WORKSTATIONS[5]. Two default CONFIGURATION PROFILES [5] are pre-programmed into theEDGE SWITCH [1] so as to enable TELEPHONE STATION FEATURES and SET-TOPBOX FEATURES to operate as follows:

[0259] A default terminal function key profile is configured so as toenable subscribers to access TELEPHONE STATION FEATURES by entering DTMFdigit sequences through the TELEPHONE STATIONS [3]. TELEPHONE STATION[3] speed-dial keys may be programmed to support these DTMF digitsequences so that they can be used as dedicated feature keys.

[0260] A default SET-TOP BOX [4] interface profile is programmed intothe EDGE SWITCH for the particular type of SET-TOP BOX [4] at thesubscriber premise. This interface profile is used internally by theEDGE SWITCH [1] to convert the vendor-specific command sequencessupported by the SET-TOP BOX [4] to be compatible with the channelselection protocol supported by the NETWORK-BASED ENHANCED SERVICES [18]providing selectable video content;

DEFINITIONS

[0261] This section contains definitions for major system elements,terms, and protocols referenced in this disclosure. Thetelecommunications industry contains a variety of views regardingexactly what comprises these elements; thus the definitions should notin all cases be considered absolute. Definitions annotated withnumerical identifiers in brackets refer to system elements that areexplicitly shown in figures.

IETF

[0262] Internet Engineering Task Force (IETF). The IETF is a standardsbody whose conventions mandate that a body of work is presentedinitially as an “Internet Draft” which either expires or is formallypromulgated to a “Request for Comment” (RFC). Both the Internet Draftand RFC documents must comply with a content format convention.

ITU-T

[0263] International Telecommunications Union—Telephony (ITU-T).

POTS

[0264] Plain Old Telephone Service. Standard analog telephone serviceprovided by the PSTN. POTS relies upon a CENTRAL OFFICE SWITCH line cardcontaining a Subscriber Line Interface Circuit (SLIC). For moreinformation, see the definition for the TELEPHONE LINE INTERFACE [1.9]below.

EDGE SWITCH [1]

[0265] DES system element that is a hardware device used to terminateIP-based voice, video, and data broadband network service at the networksubscriber (customer) premise. It is deployed as a premise-based networkelement at the carrier point of demarcation where outside wiringconnects to inside wiring, and functions as an integral service deliverycomponent of the IP CARRIER NETWORK [6]. EDGE SWITCHES are constructedaccording to a variety of form-factors as required to accommodate voice,video, and data termination requirements at the subscriber premise.

[0266] Regardless of form-factor, all EDGE SWITCHES are centrallymanaged by a SYSTEM MANAGEMENT PLATFORM [2], which is installed in thecentral office or central office equivalent. When the EDGE SWITCH isconnected to the BROADBAND ACCESS NETWORK [6.1], it registers with adefault SYSTEM MANAGEMENT PLATFORM [2]. At that time, the SYSTEMMANAGEMENT PLATFORM [2] remotely loads the EDGE SWITCH with all thesoftware necessary for it to deliver the network services (servicecapabilities) purchased by the subscriber at whose premise the EDGESWITCH has been installed. Once the EDGE SWITCH completes its systemstartup procedure with the new software load, the subscriber may thenconfigure the EDGE SWITCH according to their personal preferencesthrough a web user interface. A web application running on a WEB SERVER[11] initiates an authenticated (secure) login to the EDGE SWITCH andthereby mediates subscriber access to its features.

[0267] Architecturally, the EDGE SWITCH has two distinct “sides:” thenetwork side and the subscriber side. The network side of the EDGESWITCH incorporates a BROADBAND NETWORK INTERFACE [1.1] that physicallyconnects it to the BROADBAND ACCESS NETWORK [6.1]; it provides allnecessary electrical (and potentially optical) signal modulation andnetwork adaptation necessary to terminate broadband network access. Thenetwork side ultimately presents the IP ROUTING MODULE [1.2] in the EDGESWITCH with an IP access path through the BROADBAND ACCESS NETWORK[6.1], dynamically aggregating voice-over-IP, video-over-IP, and commondata-over-IP packet flows into a composite IP packet flow. The totalbitrate transmission requirements for this composite IP packet flow mustbe less than or equal to the total available through the BROADBANDNETWORK INTERFACE [1.1]. Central to its ability to support multi-servicedelivery through the BROADBAND NETWORK INTERFACE [1.1], the EDGE SWITCHsupports internal service logic that determines if the projectedcomposite IP packet flow that would be required to support the deliveryof all requested voice, video, and data services would exceed the totalbitrate transmission available from the network side.

[0268] The subscriber side of the EDGE SWITCH connects to TELEPHONESTATIONS [3], SET-TOP BOXES [4], and COMPUTER WORKSTATIONS [5] installedat the subscriber premise. It provides telephone services to theTELEPHONE STATIONS [3], video (multimedia) services to the SET-TOP BOXES[4], and data communication services to the COMPUTER WORKSTATIONS [5].In the case of TELEPHONE STATIONS [3], the EDGE SWITCH converts analogelectrical (and potentially digital) telephone device-level signalingand voice transmission conventions to and from IP packets containing SIPnetwork signaling information and digitally-encoded voice. In the caseof SET-TOP BOXES [4], it is assumed that device signaling informationand media content are already digitally-encoded in IP packets and thatSET-TOP BOXES [4] natively support SIP network signaling. The subscriberside supports admission control features that enable it to deny voiceand/or video calling service delivery to TELEPHONE STATIONS [3] orSET-TOP BOXES, or attenuate data service delivery to COMPUTERWORKSTATIONS [5].

[0269] Support for voice-over-IP or video-over-IP call sessions on thesubscriber side requires that the EDGE SWITCH perform a prioritized IProuting function to ensure the timely transport of IP packet flowsbi-directionally between the TELEPHONE STATIONS [3] (and SET-TOP BOXES[4]) and the IP CARRIER NETWORK [6]. As TELEPHONE STATIONS [3] (andSET-TOP BOXES [4]) answer incoming SIP call sessions or originateoutgoing SIP call sessions, the EDGE SWITCH dynamically reserves therequisite network side bandwidth on demand—effectively removing it fromthe pool of bandwidth available to COMPUTER WORKSTATIONS [5]—anddiscreetly reassigns it to media transmission. IP packets needed forreal-time voice and streaming video transmission are isolated intolabeled IP packet flows. The labeled voice and video packet flows arethen routed by the IP ROUTING MODULE [1.2] through the BROADBAND ACCESSNETWORK [6.1] at a higher priority than common data packets, thusenabling them to be routed preferentially through other elements of theIP CARRIER NETWORK [6], according to a higher quality of service thennecessary to support common data transmission.

[0270] TELEPHONE STATIONS [3] and SET-TOP BOXES [4] plugged into thesubscriber side of the EDGE SWITCH may to a certain extent bevendor-specific in the way they communicate with it. For the purpose ofnormalizing the way that end-users may access network services usingdifferent brands of TELEPHONE STATIONS [3] and SET-TOP BOXES [4], theEDGE SWITCH supports terminal adaptation features, performing devicesignaling and media format conversion bi-directionally in real-time asrequired to interoperate with SIP endpoints residing within the IPCARRIER NETWORK [6].

[0271] TELEPHONE STATIONS [3] also tend to differ from vendor to vendorin their function key layouts. For example, a telephone key dedicated todeleting a voice message will generate a tone sequence or key code thatmay not match the tone sequence or key code utilized by a particularvendor's voice messaging system for the same function. Telephonefunction key layout profiles can be programmed into the EDGE SWITCH bythe subscriber (mediated through a network-based web server) so that theEDGE SWITCH can convert a vendor-specific tone sequence or key code usedby a particular TELEPHONE STATION [3] to a user interface conventionthat can be understood by NETWORK-BASED ENHANCED SERVICES [18].

[0272] Although the SET-TOP BOXES [4] natively support SIP networksignaling and communicate through an IP connection, the EDGE SWITCH maystill be required to convert vendor-specific device signalinginformation (e.g. protocols for channel selection) to be compatible withconventions used by NETWORK-BASED ENHANCED SERVICES [18] providing videostreaming content.

[0273] The EDGE SWITCH has sufficient storage and processingcapabilities to implement an optimized subset of subscriber telephonefeatures and services that are today provided by the CENTRAL OFFICESWITCH [7.1], including certain Customer Local Access Signaling Services(CLASS) and selected PBX/Centrex features usually provided tobusinesses. Telephone services and features are provided by each EDGESWITCH to the TELEPHONE STATIONS [3] plugged into it without anyrequirement to interface a CENTRAL OFFICE SWITCH [7.1], and without anyrequirement to interface network elements such as “IP Centrex” featureservers. Inasmuch as telephone features are implemented internally bythe EDGE SWITCH, so too is the ability to generate and internally storeevent histories for subscriber access to these services. The internallystored event histories are sorted by the EDGE SWITCH such that billableevents may be periodically transmitted to a SYSTEM MANAGEMEMENT PLATFORM[2] for further processing. The SYSTEM MANAGEMEMENT PLATFORM [2]positively identifies the end user that generated the billable events bymatching the physical device address of the EDGE SWITCH that generatedthe billable events with the physical device address of an EDGE SWITCHregistered to an end user.

[0274] Private dialing plans may be cached in the EDGE SWITCH, as aresubscriber preferences and related configuration data necessary tosupport telephone feature delivery. A single EDGE SWITCH can internallystore over a year of call log data, and make that information availableto a third-party application; thus the EDGE SWITCHES deployed in thenetwork collectively function as a distributed subscriber call log database that scales with the network and is capable of real-time access bynetwork applications. An EDGE SWITCH can make its feature delivery andcall control capabilities available to a third-party application; thusthe EDGE SWITCHES deployed in the network collectively function as adistributed call control and feature delivery resource that scales withthe network and is capable of (near) real-time access by networkapplications. The capability of EDGE SWITCHES to makesubscriber-specific information (call log and Class of Service data) andcalling feature delivery remotely accessible to third-party applicationsenables new types of interactive calling services in which subscribersmay actively participate in network service delivery by the EDGESWITCHES.

[0275] Making the most intelligent use of policy data and subscriberpreferences cached within it, the EDGE SWITCH [1] attempts to connecttelephone calls and deliver telephone features in the most localizedmanner possible with minimal assistance from carrier network elements.The EDGE SWITCH [1] supports SIP network signaling natively andincorporates its own internal call routing functionality, making itpossible for telephone calls between TELEPHONE STATIONS [3] plugged intothe same EDGE SWITCH to be routed internally through its IP ROUTINGMODULE [1.2] or potentially through its MEDIA STREAM CONTROLLER [1.7].As a result, these “on-switch” call sessions do not require networkresources to support end-to-end signaling, media transmission, ortelephone device control, and thus are not significant consumers ofnetwork transmission resources.

[0276] For telephone calls between TELEPHONE STATIONS [3] that are notplugged into the same EDGE SWITCH, the call paths are established as SIPcall sessions through the IP CARRIER NETWORK [6], between EDGE SWITCHES[1]. This mode of communication is possible because each EDGE SWITCH [1]presents the TELEPHONE STATIONS [3] (and SET-TOP BOXES [4]) to the IPCARRIER NETWORK [6] as an array of intelligent SIP endpoints.

BROADBAND NETWORK INTERFACE [1.1]

[0277] Hardware subcomponent of the EDGE SWITCH [1] that physicallyconnects it to the BROADBAND ACCESS NETWORK [6.1] using any one ofnumber of OSI Layer 1 broadband technologies (e.g. coaxial cable,Ethernet cable, optical coupling, or copper wire) as required by thehost carrier. This subcomponent provides IP connectivity from OSI Layer3 (network layer) down, which includes OSI Layer 2 (data link layer) andOSI Layer 1 (physical layer). While the BROADBAND NETWORK INTERFACE maybe implemented using any type of OSI Layer 2 and OSI Layer 1 technology,it is required to aggregate all available broadband network transmissioncapacity into to single IP data service in OSI Layer 3, and then topresent an interface to that data service to the IP ROUTING MODULE[1.2]. It is anticipated that in some implementations, the BROADBANDNETWORK INTERFACE may be support programmable logic that would enable itto be customized or upgraded, potentially remotely by the SYSTEMMANAGEMENT PLATFORM [2].

IP ROUTING MODULE [1.2]

[0278] Hardware subcomponent of the EDGE SWITCH [1] that performs all IP(OSI Layer 3) packet routing functions. It communicates with theBROADBAND ACCESS NETWORK [6.1] through the BROADBAND NETWORK INTERFACE[1.1]. It provides IP-based video stream connectivity for SET-TOP BOXES[4] through the VIDEO EXTENDER MODULE INTERFACE [1.4] and provides IPdata connectivity to COMPUTER WORKSTATIONS [5] through the COMPUTER DATAINTERFACE [1.5]. It provides voice stream connectivity for TELEPHONESTATIONS [3] through its integration with the MEDIA STREAM CONTROLLER[1.7] and PACKETIZATION COPROCESSOR [1.6].

[0279] This subcomponent enforces preferential routing policies toensure higher priority voice and video packets are routed in a timelyfashion. The IP ROUTING MODULE prioritizes packets for routing basedupon a labeling mechanism that assigns them to predefined QoS standards.Higher priority packets are classified and scheduled for processingahead of lower priority packets. The IP ROUTING MODULE supportstransmission pathways in which both connection endpoints correspond tovoice or video terminals plugged into the same EDGE SWITCH [1], andsupports a programmatic interface such that it may be directlycontrolled by software in the IP ROUTING SYSTEM [1.4].

POWER SUPPLY [1.3]

[0280] Hardware subcomponent of the EDGE SWITCH [1] that conditionspower from a DC POWER SOURCE [6.2] prior to making it available to theelectronic components of the EDGE SWITCH [1]. This subcomponent providesfor surge protection and may be implemented with battery functionalityso that it is able to continue powering the EDGE SWITCH [1] for a periodof time after the DC POWER SOURCE [6.2] has failed. The POWER SUPPLY[1.3] may be implemented with a switch that enables it to be switchedbetween line power (from the BROADBAND ACCESS NETWORK [6.1] physicalconnection) or from a premise-based power source.

COMPUTER DATA INTERFACE [1.4]

[0281] Hardware subcomponent of the EDGE SWITCH [1] integrated withexternal cabling interface used to plug in one or more COMPUTERWORKSTATIONS [5] to the EDGE SWITCH [1]. The COMPUTER DATA INTERFACEsupports bidirectional IP data paths used for common data transportbetween the IP ROUTING MODULE [1.2] and the COMPUTER WORKSTATIONS [5].If more than one COMPUTER WORKSTATION [5] is used, an ETHERNET HUB [9]or ETHERNET SWITCH [20] may be used for the purpose of distributing datastreams to more than one COMPUTER WORKSTATION [5] at the same time.

VIDEO STREAMING DEVICE INTERFACE [1.5]

[0282] Hardware subcomponent of the EDGE SWITCH [1] integrated withexternal cabling interface that is used to connect SIP video streamingdevices such as SET-TOP BOXES [4]. SIP media streaming devices nativelysupport SIP network signaling. The VIDEO STREAMING DEVICE INTERFACEsupports bidirectional IP data paths used for SIP network signaling andreal-time media streaming between the IP ROUTING MODULE [1.2] and one ormore SET-TOP BOXES [4]. If more than one SET-TOP BOX [4] is plugged intothe EDGE SWITCH [1], an ETHERNET SWITCH [20] should be used so as toensure sufficient bandwidth necessary to maintain network quality ofservice for all video call sessions.

PACKETIZATION COPROCESSOR [1.6]

[0283] Hardware subcomponent of the EDGE SWITCH [1] that is used by theMEDIA STREAM CONTROLLER [1.7] to assist in real-time processing of voicemedia and voice-related IP data packets transmitted through the IPROUTING MODULE [1.2]. Most packet processing carried out by thePACKETIZATION COPROCESSOR [1.6] is in support of IETF RFC 1889 on RTP: ATransport Protocol for Real-Time Applications, and IEFT RFC 2833 on RTPPayload for DTMF Digits, Telephony Tones and Telephony Signals. ThePACKETIZATION COPROCESSOR may also be used for packet labeling to markvoice-related IP data packets originating at the TELEPHONE LINEINTERFACE [1.9] with the appropriate quality of service marker prior totheir introduction to the IP ROUTING MODULE [1.2]. While someimplementations may choose to implement voice encoding and decodingalgorithms on the DIGITAL SIGNAL PROCESSOR [1.8], it is also possiblethat the PACKETIZATION COPROCESSOR [1.6] could be used for this purpose.

MEDIA STREAM CONTROLLER [1.7]

[0284] Hardware subcomponent of the EDGE SWITCH [1] used tointerconnect, mix, and process full and half-duplex media streams. For amedia stream to be interconnected, mixed, or processed by the MEDIASTREAM CONTROLLER, at least one of its endpoints must terminate on it,whereas the other endpoint of that media stream may terminate either onthe TELEPHONE LINE INTERFACE [1.9] or within the IP CARRIER NETWORK [6](transmitted through the BROADBAND NETWORK INTERFACE [1.1]).

[0285] The MEDIA STREAM CONTROLLER can be used to interconnect two mediastreams to create a full or half-duplex media session. It caninterconnect three or more media streams to create a fully meshedconference. The MEDIA STREAM CONTROLLER enables multi-party conferencecalls of this type through the use of conferencing resources. All mediastreams that are interconnected through a conferencing resource willreceive the media contents of all other media streams connected to thatconferencing resource. Media transmission to or from any media streamendpoint can be enabled or disabled, and signal processing algorithmsmay be applied to any stream.

[0286] The MEDIA STREAM CONTROLLER physically interfaces the IP ROUTINGMODULE [1.2] on the network side of the EDGE SWITCH [1] and theTELEPHONE LINE INTERFACE [1.9] on the subscriber side. In order to moreefficiently transmit voice in real-time through the BROADBAND ACCESSNETWORK [6.1] (according to IETF RTP protocol standards), the MEDIASTREAM CONTROLLER [1.7] uses the PACKETIZATION COPROCESSOR [1.6] as adedicated peripheral computing resource for packet processing. In likefashion, the MEDIA STREAM CONTROLLER [1.7] uses the DIGITAL SIGNALPROCESSOR [1.8] as a dedicated peripheral computing resource to rundigital signal processing algorithms that may be applied dynamically tomedia streams as needed.

DIGITAL SIGNAL PROCESSOR [1.8]

[0287] Hardware subcomponent of the EDGE SWITCH [1] that is a dedicatedperipheral computing resource used to provide signal processingfunctions to the MEDIA STREAM CONTROLLER [1]. It may be implemented asan independent device or its capabilities may be integrated directlyinto the MEDIA STREAM CONTROLLER [1.7]. This subcomponent supportsrunning various digital signal processing algorithms that may includeDTMF digit detection, DTMF digit generation, network tone detection,network tone generation, noise cancellation, comfort noise generation,echo cancellation, voice onset detection, voice offset detection, modem(fax) tone detection, and media stream encoding/decoding/transcoding.

TELEPHONE LINE INTERFACE [1.9]

[0288] Hardware subcomponent of the EDGE SWITCH [1] integrated withexternal cabling interface that is used to connect TELEPHONE STATIONS[3]. TELEPHONE STATIONS [3] do not natively support SIP networksignaling and as a result cannot present themselves to an IP network asSIP network signaling endpoints without assistance from the EDGE SWITCH[1].

[0289] The TELEPHONE LINE INTERFACE may also be adapted to support avariety of proprietary telephones, such analog POTS telephones, digitalPBX telephones and various Centrex telephones.

[0290] If used to connect POTS telephones, the TELEPHONE LINE INTERFACEsupports many of the BORSCHT functions, including: (B) Battery feed topower the subscriber's telephone, (R) Ringing signal to the subscriberstelephone, (S) Supervision to detect caller off-hook, calls in progress,calls terminated, (C) Coding of analog voice signals into PCM digitalformat, (H) Hybrid transformer for conversion from two-wire tofour-wire, and filtering to provide impedance match to remove orminimize echoes, and (T) Testing of the local loop and circuits of theswitching equipment to detect faults and provide maintenance. Each POTSservice interface provided by the TELEPHONE LINE INTERFACE [1.9] is abasic two-wire “Tip and Ring” interface that is translated into thefour-wire (balanced pair) at the point where it interfaces the MEDIASTREAM CONTROLLER [1.7].

CENTRAL PROCESSING UNIT [1.10]

[0291] Hardware subsystem of the EDGE SWITCH [1] consisting of varioussubcomponents that include a main processor, peripheral controllers andmemory cache devices necessary for it to function as a stand-alonecomputer running a real-time, preemptive, multi-tasking operatingsystem. The CENTRAL PROCESSING UNIT provides supervisory control,directly or indirectly, for all EDGE SWITCH [1] features and functions.It interfaces RANDOM ACCESS MEMORY [1.11], utilizing it to providememory needed to run the operating system and various applicationprograms; it interfaces NON-VOLATILE MEMORY [1.11], utilizing it tostore vital system configuration parameters and as a FILE SYSTEM [1.23];it interfaces both the MEDIA STREAM CONTROLLER [1.7] and the IP ROUTINGMODULE [1.2] through a system bus or similar means, utilizing each as adedicated peripheral computing resource (under software control) toimplement media connectivity and IP routing operations respectively.

RANDOM ACCESS MEMORY [1.11]

[0292] Hardware subsystem of the EDGE SWITCH [1] consisting of any arrayof solid-state storage devices configured to provide randomlyaddressable memory directly accessible to the CENTRAL PROCESSING UNIT[1.10]. The storage devices that comprise this subsystem providevolatile memory whose contents are considered to be undefined after asystem reset cycle and must be initialized prior to use.

NON-VOLATILE MEMORY [1.12]

[0293] Hardware subsystem of the EDGE SWITCH [1] consisting of any arrayof solid-state storage devices configured to provide block addressablememory accessible to the CENTRAL PROCESSING UNIT [1.10] using directmemory access (DMA) or equivalent means. The storage devices thatcomprise this subsystem user non-volatile memory whose contents areretained between system reset cycles.

NETWORK ADAPTATION LAYER [1.13]

[0294] EDGE SWITCH [1] subsystem comprised of software, firmware, orother programmable logic (or combination thereof) that is used tocontrol or impart functionality into the BROADBAND NETWORK INTERFACE[1.1]. This programmable subsystem makes it possible for the EDGE SWITCH[1] to adapt to a variety of OSI Layer 1 and 2 technologies supported bythe BROADBAND ACCESS NETWORK [6.1]. The NETWORK ADAPTATION LAYERprovides all of the control logic necessary to enable the BROADBANDNETWORK INTERFACE [1.1] to aggregate all available broadband networktransmission capacity into to single IP data service in OSI Layer 3, andthen to present an interface to that data service to the IP ROUTINGMODULE [1.2].

IP ROUTING SYSTEM [1.14]

[0295] Software subsystem of the EDGE SWITCH [1] consisting of softwarecomponents and related applications necessary to control the IP ROUTINGMODULE [1.2]; this software subsystem incorporates an IP protocol stackand implements IP routing services necessary to support voice, video,and data communications through the IP CARRIER NETWORK [6]. Softwaremodules within the IP ROUTING SYSTEM support a programmable firewall,Network Address Translation (NAT), Dynamic Host Configuration Protocol(DHCP), and Virtual Private (data) Networking (VPN).

[0296] The IP ROUTING SYSTEM may utilize the FILE SYSTEM [1.23] to storerouting tables. It will support IPv6 (the current build to standard).IPv6 provides both enhanced addressing capabilities as well as supportfor the quality of service capabilities previously only found in ATMimplementations. Thus, by supporting IPv6, the IP ROUTING SYSTEM mayemploy open shortest path first (OSPF) routing to request a path to thedesired endpoint for voice, video, and data packet transmission.

RTP PROTOCOL STACK [1.15]

[0297] Software subcomponent in the EDGE SWITCH [1] that implementssupport for IETF RFC 1889 on RTP: A Transport Protocol for Real-TimeApplications (RTP), and its adjunct protocol IETF RFC 2833 on RTPPayload for DTMF Digits, Telephony Tones and Telephony Signals. Most orall of the RTP PROTOCOL STACK software may run on the PACKETIZATIONCOPROCESSOR [1.6]. RTP is the media transmission protocol used by theDES to transmit all real-time voice and video media streams through theIP CARRIER NETWORK [6].

[0298] RFC 2833 describes a means by which DTMF digits, telephone tones,and telephony signals are transmitted “out of band” by encoding them asnumerical codes that are inserted into special-purpose RTP packets. RFC2833 is used when a selected voice media stream encoding format islikely to render these DTMF digits, telephone tones, and telephonysignals unintelligible to digital signal processors when the mediastream is decoded at the receiving end of the session.

[0299] The RTP PROTOCOL STACK is utilized by the ABSTRACT TELEPHONECONTROLLER [1.19] as a means to establish real-time media streamsessions (i.e. bearer channel connections) between SIP network signalingendpoints within the IP CARRIER NETWORK [6]. RTP sessions maintained bythe RTP PROTOCOL STACK are physically associated with media streamendpoints on the MEDIA STREAM CONTROLLER [1.7] under the control of theABSTRACT TELEPHONE CONTROLLER [1.19]. The RTP PROTOOL STACK uses thedata communication services of the IP ROUTING SYSTEM [1.14] to supportIP-based media transmission between a media stream endpoint (i.e. port)on the MEDIA STREAM CONTROLLER [1.7] and a media stream endpoint in theIP CARRIER NETWORK [6] (or potentially with another media streamendpoint also on the MEDIA STREAM CONTROLLER [1.7] in the case of a callsession that is internal to the EDGE SWITCH [1]).

SIP PROTOCOL STACK [1.16]

[0300] Software subcomponent in the EDGE SWITCH [1] that implementssupport for the “SIP Proxy Server” functionality described further inthis disclosure (see SIP PROXY SERVER [12]) and in IETF RFC 2543 on SIP:Session Initiation Protocol (SIP). The SIP PROTOCOL STACK alsoimplements support for IETF RFC 2327 on SDP: Session DescriptionProtocol (SDP). SDP is an adjunct protocol to SIP and is used by SIPnetwork signaling endpoints participating in a call session to describeto each other the detailed characteristics of the voice or video mediastreams (i.e. bearer channels) that they are capable of receiving fromeach other.

[0301] The EDGE SWITCH [1] represents each TELEPHONE STATION [3]internally as a SIP network signaling endpoint to the IP CARRIER NETWORK[6] by associating it with particular E.164 dialing number that isrecognized by the SIP PROTOCOL STACK. The ABSTRACT CALL MODEL [1.20]supports a telephone gateway function in which a SIP User Agent is usedto perform SIP network signaling endpoint functions on behalf of eachTELEPHONE STATION [3] plugged into the TELEPHONE LINE INTERFACE [1.9].This SIP User Agent directs its SIP network signaling operations to theSIP PROTOCOL STACK, using it as its default SIP Proxy Server.

[0302] Although a SET-TOP BOX [4] natively supports SIP networksignaling and is an actual SIP network signaling endpoint (i.e. containsa SIP User Agent), it exchanges SIP messages through the SIP PROTOCOLSTACK on the EDGE SWITCH [1]. The SIP User Agent in the SET-TOP BOX [4]directs its SIP network signaling operations to the SIP PROTOCOL STACK,using it as its default SIP Proxy Server.

[0303] The SIP PROTOOL STACK uses the data communication services of theIP ROUTING SYSTEM [1.14] to support IP-based SIP network signalingoperations between itself and the IP CARRIER NETWORK [6].

HTTP PROTOCOL STACK [1.17]

[0304] Software subcomponent in the EDGE SWITCH [1] that implementssupport for IETF RFC 2068 on Hypertext Transfer Protocol—HTTP Version1.1 (HTTP). HTTP provides a generalized means for two programs toexchange text and data files over an IP network. The operationalsemantics of HTTP are based on the notion of a “HTTP client” (webrowser) that makes requests for information and an “HTTP server” (webserver) that responds to those requests. The HTTP PROTOCOL STACKimplements support for both the “HTTP client” and the “HTTP server”elements of HTTP.

[0305] Support for the “HTTP client” element provides a means by whichthe XML MGMT INTERFACE [1.21] may communicate with the SYSTEM MANAGEMENTPLATFORM [2] (e.g. to report updated subscriber preferences or to uploadbilling records). Support for the “HTTP server” element makes itpossible for any computer implementing the “HTTP client,” such as theSYSTEM MANAGEMENT PLATFORM [3] or the WEB SERVER [11], to communicatewith the XML MGMT INTERFACE [1.21] for the purposes of systemmanagement, service provisioning or subscriber interaction (e.g. toaccess its features and call log data).

[0306] A computer attempting to communicate with the EDGE SWITCH [1]using HTTP must log-in to the XML MGMT INTERFACE [1.21] and authenticateitself as a valid user. Information exchange and remote activation ofEDGE SWITCH [1] features by an external computer is based onXML-encoding (via XML MGMT INTERFACE [1.21]) for both the requests andthe responses thereto. The HTTP PROTOOL STACK uses the datacommunication services of the IP ROUTING SYSTEM [1.14] to supportIP-based HTTP sessions between the “HTTP client” and “HTTP server”instances that it maintains internally, and other “HTTP client” and“HTTP server” instances in the IP CARRIER NETWORK [6].

SNMP PROTOCOL STACK [1.18]

[0307] Software subcomponent in the EDGE SWITCH [1] that implementssupport for IETF RFC 1157 on SNMP: A Simple Network Management Protocol(SNMP). SNMP is a protocol by which management information for a networkelement may be inspected or altered by remote users. It is used tocommunicate management information between network management stationsand “SNMP agents” (specialized software processes) running on themanaged network elements. The SNMP functional paradigm for monitoringand control is designed to be extensible to accommodate additional,possibly unanticipated aspects of network operation and management;thus, the SNMP architecture is adaptable to accommodate the managementof EDGE SWITCHES [1] by the SYSTEM MANAGEMENT PLATFORM [2].

[0308] In the DES management paradigm, the SYSTEM MANAGEMENT PLATFORM[2] functions as the primary management station for a select populationof EDGE SWITCHES [1]. The SNMP PROTOCOL STACK uses the datacommunication services of the IP ROUTING SYSTEM [1.14] to support SNMPsessions between the SYSTEM MANAGEMENT PLATFORM [2] and the DEVICE MGMTAGENTS [1.22].

ABSTRACT TELEPHONE CONTROLLER [1.19]

[0309] Software subcomponent of the EDGE SWITCH [1] that logicallydefines a full-featured, abstract telephone device control model thatenables a higher-level application program to programmatically controlthe operation of TELEPHONE STATIONS [3] plugged into the TELEPHONE LINEINTERFACE [1.9], including the ability to interconnect, mix, and processfull and half-duplex media streams associated with them. It implementsfeatures of this abstract telephone device control model to the fullestextent possible by invoking the MEDIA STREAM CONTROLLER [1.7] as a mediacontrol resource and the TELEPHONE LINE INTERFACE [1.9] as a telephonecontrol resource. Certain features such as tone detection, tonegeneration and media transcoding are supported by the MEDIA STREAMCONTROLLER [1.8] working in conjunction with the DIGITAL SIGNALPROCESSOR [1.8].

[0310] There is no concept of a “call session” in this telephone controlmodel since only telephone features and media streams are managed. The“call session” concept is maintained in the ABSTRACT CALL MODEL [1.20],which functions as the “higher-level application program”—an applicationwith knowledge of all SIP network signaling endpoints involved in agiven call session.

[0311] The telephone control features support enabling or disablingdetection of telephone events originating from the TELEPHONE LINEINTERFACE [1.9] (e.g. detection of on-hook, off-hook, hook flash,feature keys, and calls in progress, etc.). Telephone control featuresalso support various device-level telephone features such as activatingstandard ring signaling, enabling distinctive ringing, enabling ordisabling stutter dial-tone, activating or deactivating themessage-waiting indicator lamp or to display text on a telephone LCDscreen.

[0312] The media stream control features of the ABSTRACT TELEPHONECONTROLLER support programmatically enabling or disabling mediatransmission to or from any media stream endpoint, particularly withrespect to media stream endpoints associated with TELEPHONE STATIONS [3]plugged into the TELEPHONE LINE INTERFACE [1.9]. Conferencing featuresenable multi-party calls (e.g. 3-way calling, n-way calling) through theuse of conferencing resources that can be applied programmatically.Digital signal processing algorithms may be applied programmatically toany stream to support tone detection, tone generation, echo cancellationand media transcoding, for example.

[0313] The media stream control model used by the ABSTRACT TELEPHONECONTROLLER reflects that of the underlying MEDIA STREAM CONTROLLER [1.7]used to realize its features. In some respects, the control model issimilar to that used by time division multiplex (TDM) telephony devicesthat support multi-line call and media control interfaces. It assumesthat at least one endpoint of a media stream terminates on a MEDIASTREAM CONTROLLER [1.7] port and that the other endpoint of that samemedia stream terminates either on the TELEPHONE LINE INTERFACE [1.9] oron an endpoint within the IP CARRIER NETWORK [6] (transmitted throughthe BROADBAND NETWORK INTERFACE [1.1] by the PACKETIZATION COPROCESSOR[1.6] using RTP). This control model also assumes that any two mediastream endpoints terminating on MEDIA STREAM CONTROLLER [1.7] ports(regardless of where their other endpoints terminate) may beinterconnected through the MEDIA STREAM CONTROLLER [1.7] to create afull or half-duplex media session between the two far-end endpoints.

ABSTRACT CALL MODEL [1.20]

[0314] Software subcomponent of the EDGE SWITCH [1] that logicallydefines an abstract call control model and adjunct telephone feature setthat enables event-driven CALL PROCESSING APPLICATIONS [1.23.2] todeliver network service to subscribers through TELEPHONE STATIONS [3]and SET-TOP BOXES [4] plugged into the EDGE SWITCH [1]. The ABSTRACTCALL MODEL implements its abstract call control model and telephonefeature set to the fullest extent possible by (a) invoking networksignaling operations available through the SIP PROTOCOL STACK [1.16] and(b) invoking telephone features, media streaming capabilities, andrelated digital signal processing features available through theABSTRACT TELEPHONE CONTROLLER [1.19]. By integrating with these softwareelements, the ABSTRACT CALL MODEL becomes the nexus between the IPCARRIER NETWORK [6] and service logic contained in CALL PROCESSINGAPPLICATIONS [1.23.2] that are stored within the FILE SYSTEM [1.23].

[0315] CALL PROCESSING APPLICATIONS [1.23.2] define how the EDGE SWITCH[1] responds to certain events—they define the EDGE SWITCH [1] workflowin response to network signaling events and device-level telephoneevents—and consequently they in effect define the network services thatare provided to the subscriber through TELEPHONE STATIONS [3] andSET-TOP BOXES [4].

[0316] The ABSTRACT CALL MODEL supports five distinct functions that areimplemented to the fullest extent possible in a device-independentfashion:

[0317] (1) Telephone Gateway Function

[0318] (2) Telephone Feature Delivery Function

[0319] (3) Terminal Adaptation Function

[0320] (4) Calling Service Delivery Function

[0321] (5) Admission Control Function

[0322] The Telephone Gateway Function and the Telephone Feature DeliveryFunction are only applicable to call sessions involving TELEPHONESTATIONS [3]. Both TELEPHONE STATIONS and SET-TOP BOXES [4] make use ofthe other three functions. FIG. 7 depicts the EDGE SWITCH [1] call modelin some detail, showing specifically how the five ABSTRACT CALL MODELfunctions above are implemented within the EDGE SWITCH [1] softwarearchitecture.

[0323] For TELEPHONE STATIONS [3] to participate in call sessions usingSIP network signaling, the ABSTRACT CALL MODEL [1.20] performs aTelephone Gateway Function in which it actively convertsvendor-specific, device-level telephone signaling (through its interfaceto the ABSTRACT TELEPHONE CONTROLLER [1.19]) into SIP network signalingoperations. As depicted in FIG. 7, the ABSTRACT CALL MODEL maintains aninstance of a SIP User Agent for each TELEPHONE STATION [3] plugged intothe EDGE SWITCH [1]. This SIP User Agent is registered with the SIPPROTOCOL STACK [1.16], using it as its default SIP Proxy Server. The SIPPROTOCOL STACK [1.16] knows which registered SIP User Agent instancecorresponds to which dialing number, thus it can direct SIP networksignaling to it based on dialing number addressing.

[0324] Certain “TELEPHONE EVENTS” received from the ABSTRACT TELEPHONECONTROLLER [1.19], and/or SIP network signaling events from the SIPPROTOCOL STACK [1.16], trigger the ABSTRACT CALL MODEL to invoke a CALLPROCESSING APPLICATION [1.23.2] to apply service logic to the callsession. This service logic will respond to the received event with someprogrammed action.

[0325] Since the ABSTRACT CALL MODEL retains device-level control overTELEPHONE STATIONS [3] plugged into the EDGE SWITCH [1] (through itssoftware integration with the ABSTRACT TELEPHONE CONTROLLER [1.19]) itsupports a Telephone Feature Delivery Function in which it may exertdevice-level control over TELEPHONE STATIONS [3] (see “TELEPHONECONTROL” in FIG. 7). Commands sent to the ABSTRACT TELEPHONE CONTROLLER[1.19] are ultimately directed to the TELEPHONE LINE INTERFACE [1.9],and in some cases to the actual TELEPHONE STATION [3] itself (e.g. todisplay text on an LCD screen, activate a message-waiting indicationlamp, or to initiate distinctive ring signaling).

[0326] The Terminal Adaptation Function may take place as an adjunct tothe Telephone Gateway Function when the ABSTRACT CALL MODEL determinesthat a CONFIGURATION PROFILE [1.23.5] contains a telephone function keyprofile that has been programmed into the EDGE SWITCH [1] for aparticular type of TELEPHONE STATION [3]. As a result, the ABSTRACT CALLMODEL converts vendor-specific tone sequences or key codes to complywith an appropriate user interface convention (in accordance with modelset forth by the function key layout profile).

[0327] As an example of terminal adaptation, a speed-dial feature key ona POTS telephone may be programmed to generate a DTMF tone sequence suchas “#45” when pressed. A CONFIGURATION PROFILE [1.23.5] on the EDGESWITCH [1] contains a telephone function key profile specifying that anytime the DTMF digit sequence “#45” is detected from that particular POTStelephone, a virtual function key code called “TRANSER” is generated andpassed as a virtual function key event to the CALL PROCESSINGAPPLICATION [1.23.2] currently executing. Upon receiving the “TRANSFER”virtual function key event, the CALL PROCESSING APPLICATION [1.23.2]will interpret the next series of DTMF digits as the dialing number towhich the current call session should be transferred. From the user'sperspective, the programmed speed-dial key functions as a dedicated“TRANSFER” key.

[0328] In FIG. 7, two SIP call sessions are shown to illustratepotential SIP protocol message flow. One example shows a SET-TOP BOX [4](shown as terminal “A”) connected in a multimedia SIP call session toanother SET-TOP BOX [4] (shown as terminal “C”). Presumably cameras areconnected to the SET-TOP BOXES [4] to enable two-way videocommunications. In a second example, a TELEPHONE STATION [3] (shown asterminal “B”) is connected in a voice SIP call session to anotherTELEPHONE STATION [3] (shown as terminal “D”).

[0329] Thus, in summary: terminal A represents a near-end SIP User Agentcommunicating with terminal C, which represents a far-end SIP UserAgent. Terminal B represents a near-end SIP User Agent communicatingwith terminal D, which represents a far-end SIP User Agent.

[0330] The SET-TOP BOX [4] plugged into the VIDEO STREAMING DEVICEINTERFACE [1.5] (terminal A) and the TELEPHONE STATION [3] plugged intoTELEPHONE LINE INTERFACE [1.9] (terminal B)—the near-end SIP UserAgents—are both registered with the SIP PROTOCOL STACK [1.16], using itas their default SIP Proxy Server. Thus, the client list for the SIPProxy Server (i.e. SIP PROTOCOL STACK [1.16]) will treat them both in aconsistent fashion as SIP network signaling endpoints representingnear-end terminals plugged into the EDGE SWITCH [1].

[0331] The SIP PROTOCOL STACK [1.16], functioning the same as any SIPProxy Server, will forward SIP protocol messages between the near-endSIP network signaling endpoints (terminals A & B) through the IP CARRIERNETWORK [6] to and from the far-end SIP network signaling endpoints(terminals C & D) to which they are respectively connected. It is therole of a SIP Proxy Server to make network signaling events (shown as“SIGNALING EVENTS”) available to an application so that service logiccan applied to the SIP call sessions. In the EDGE SWITCH [1] softwarearchitecture, the integration between the SIP PROTOCOL STACK [1.16] andthe ABSTRACT CALL MODEL [1.20] serves this purpose.

[0332] The Calling Service Delivery Function occurs when the ABSTRACTCALL MODEL, triggered by SIP network signaling events (i.e. SIGNALINGEVENTS) from the far-end terminals or near-end terminals, retrievesstored service logic and executes it as a means to participate in theassociated SIP call sessions. Service logic for the EDGE SWITCH [1] iscontained within CALL PROCESSING APPLICATIONS [1.23.2] stored in theFILE SYSTEM [1.23].

[0333] The ABSTRACT CALL MODEL will recognize certain signaling events(such as an incoming call from the network side) that will trigger it torespond by executing a CALL PROCESSING APPLICATION [1.23.2] that iscurrently loaded in memory. Or alternately, certain events might triggerthe ABSTRACT CALL MODEL to retrieve a new CALL PROCESSING APPLICATION[1.23.2] and execute it anew. Certain CALL PROCESSING APPLICATIONS[1.23.2] will actively query SUBSCRIBER SERVICE PROFILES [1.23.4] todetermine the Class of Service for the TELEPHONE STATION [3] involved inthe call.

[0334] Ultimately, Calling Services take effect by active participationof CALL PROCESSING APPLICATION [1.23.2] in SIP call sessions; theyperform telephone control operations, call control operations and makeuse of signaling information directly, such as the dialing numbers ofthe calling and called party.

[0335] The Admission Control Function occurs each time a SET-TOP BOX [4]or TELEPHONE STATION [3] attempts to originate or answer a call. TheCALL PROCESSING APPLICATION [1.23.2] contains the service logic used tosupervise the connection attempt. This service logic will consider twogating factors that could potentially cause it to deny admission to EDGESWITCH [1] network services: (a) Class of Service and (b) physicalresource availability. The Class of Service assigned to the TELEPHONESTATION [3] or SET-TOP BOX [4] will determine the exact service logicthat should be applied to a connection attempt.

[0336] For example, if the Class of Service specifies that outgoingcalls to a “900” number from a certain TELEPHONE STATION [3] are notpermitted, and a connection attempt to a “900” number is the connectionbeing attempted, then the CALL PROCESSING APPLICATION [1.23.2] will denyit.

[0337] If the service logic allows a connection attempt to proceed onthe basis of it complying with the Class of Service, the CALL PROCESSINGAPPLICATION [1.23.2] must then determine if sufficient physicalresources are available to complete the transaction. Among otherconsiderations, the service logic supported by the CALL PROCESSINGAPPLICATION [1.23.2] will need to ensure that the new connection willnot exceed the maximum number of call sessions supported by the EDGESWITCH [1] configuration, and that there is adequate network bandwidth,internal routing capability, and digital signal processing resources tosupport the connection. If all these criteria are met, the connectionattempt is allowed to proceed.

[0338] The Terminal Adaptation Function as applied to SET-TOP BOXES [4]may take place as an adjunct to the Calling Service Delivery Function.When the ABSTRACT CALL MODEL determines that one of the CONFIGURATIONPROFILES [1.23.5] contains a SET-TOP BOX [4] interface profile that hasbeen programmed into the EDGE SWITCH [1] for a particular type ofSET-TOP BOX [4], it will use this profile to convert the vendor-specificcommand sequences supported by that SET-TOP BOX [4] to comply with anappropriate interface convention.

[0339] Since the SET-TOP BOX [4] interfaces the EDGE SWITCH [1] throughan routed IP data path, the ABSTRACT CALL MODEL can only exertdevice-level control of SET-TOP BOX [4] features indirectly bycommunicating commands to it through the VIDEO STREAMING DEVICEINTERFACE [1.5]. Commands directed to the SET-TOP BOX [4] may supportdisplaying text over the video image (text overlay) or muting of audiooutput, for example.

[0340] As a further example of the Terminal Adaptation Function, theSET-TOP BOX [4] at the near-end may use a channel selection protocolincompatible with NETWORK-BASED ENHANCED SERVICES [18] at the far-endused to provide selectable video content; thus the protocol used at thenear-end must be converted to an appropriate interface convention usedat the far-end.

XML MGMT INTERFACE [1.21]

[0341] XML (extensible Markup Language) is a set of conventions used tocreate text formats that enable data to be structured as lists of textexpressions. The XML MGMT INTERFACE [1.12] is a software subcomponent inthe EDGE SWITCH [1] that provides a secure, XML-based data exchangeinterface for the purposes of (a) enabling a remote user to accessinformation stored in various EDGE SWITCH [1] databases and (b) enablinga remote user to access features and functions supported by the EDGESWITCH [1], including call control operations and the ability toremotely activate certain DEVICE MGMT AGENTS [1.22].

[0342] Database information and feature-related parameters exchangedthrough this interface are structured according to these XML text formatconventions, making it possible for them to be easily specified and/orinterpreted by remote users. Remote users, which might include webapplications and network management stations, access the XML MGMTINTERFACE through the HTTP PROTOCOL STACK [1.17].

DEVICE MGMT AGENTS [1.22]

[0343] Software applications integrated into the EDGE SWITCH [1] thatmay be activated to perform diagnostic functions, system softwareupgrades, feature testing, automated reporting, and other related devicemanagement tasks. The DEVICE MANAGEMENT AGENTS may be activatedinternally by EDGE SWITCH [1] software processes or remotely by variousapplications and network management stations through the XML MGMTINTERFACE [1.21] and/or the SNMP PROTOCOL STACK [1.18]. Certain DEVICEMANAGEMENT AGENTS may access databases on the FILE SYSTEM [1.23] for thepurpose of accessing event records in the EVENT RECORD REPOSITORY[1.23.1] or to access CONFIGURATION PROFILES [1.23.5], for example.

FILE SYSTEM [1.23]

[0344] Software subcomponent in the EDGE SWITCH [1] that functions asdirectory-based file system; it supports standard file system operatingsemantics (open, close, read, write) and hierarchical directorystructures, using the NON-VOLATILE MEMORY [1.12] as the physical storagedevice. The file system is implemented as a system resource, accessiblethrough the operating system functions calls.

EVENT RECORD REPOSITORY [1.23.1]

[0345] Database stored on FILE SYSTEM [1.23] that contains event recordsgenerated by various software processes running on the EDGE SWITCH [1].Event records stored in the EVENT RECORD REPOSITORY [1.23.1] areselectively generated by internal software processes according to theEDGE SWITCH [1] device configuration. Examples of the types of eventsthat are stored include those that relate to basic system operations,detailed call session events for all incoming and outgoing calls, useraccess to calling features, detected error conditions, softwarecomponent updates, and changes to subscriber preferences.

CALL PROCESSING APPLICATIONS [1.23.2]

[0346] Collection of software program files (applications) stored on theFILE SYSTEM [1.23] that are used by the EDGE SWITCH [1] to supportnetwork service delivery to users. CALL PROCESSING APPLICATIONS areinvoked by the ABSTRACT CALL MODEL [1.20]. They define the service logicfor all network services delivered to subscribers through TELEPHONESTATIONS [3] and SET-TOP BOXES [4]. They may function as call controlagents that determine the progression of the call session, and/or theymay function as device control agents that perform various telephonegateway and feature delivery functions.

[0347] They can reference other CALL PROCESSING APPLICATIONS [1.23.2],enabling the implementation of call control services (calling services)that impose no upper limit on the complexity of service logic that maybe supported. The CALL PROCESSING APPLICATIONS are responsible forgenerating call-related event histories and storing them in the EVENTRECORD REPOSITORY [1.23.1] as the call session proceeds. In creatingconnections, the CALL PROCESSING APPLICATIONS rely upon call routinginformation stored in the LOCAL CALL ROUTING TABLES [1.23.3]. Inrendering calling services, the CALL PROCESSING APPLICATIONS rely uponsubscriber capabilities and personal preferences stored along with Classof Service information in the SUBSCRIBER SERVICE PROFILES [1.23.4]

LOCAL CALL ROUTING TABLES [1.23.3]

[0348] Database stored on FILE SYSTEM [1.23] that contains call routinginformation used by the EDGE SWITCH [1] for voice and video (multimedia)call set-up. Call routing tables include lists of dialing numbers andrelated address information used by CALL PROCESSING APPLICATIONS[1.23.2] to create connections between SIP network signaling endpoints.The LOCAL ROUTING TABLES store the dialing numbers of TELEPHONE STATIONS[1] physically plugged into the EDGE SWITCH [1], as well as dialingnumbers needed to access PSTN GATEWAYS[8] installed within the IPCARRIER NETWORK [6] for the purpose of enabling voice call sessions toPSTN [7] endpoints.

[0349] Stored call routes provide default dialing numbers of Emergency911 platforms to which TELEPHONE STATIONS [3] will automaticallyconnected when 911 is dialed.

[0350] Tables of subscriber-programmed speed-dialing numbers may also bestored in call routing tables (managed by the subscriber or a remoteuser through an application running on a WEB SERVER [11]), making itpossible for the TELEPHONE STATIONS [3] to support advancedspeed-dialing functions without having to store the speed-dialingnumbers within the TELEPHONE STATION [3].

[0351] LOCAL CALL ROUTING tables also store translation tables needed tosupport private telephone networking features, which include privatedialing plans that use abbreviated dialing. Due to the substantialstorage and processing capacity of the EDGE SWITCH [1], large dialingplans containing potentially tens of thousands of entries could beaccommodated.

SUBSCRIBER SERVICE PROFILES [1.23.4]

[0352] Database stored on FILE SYSTEM [1.23] that containssubscriber-specific information used by the EDGE SWITCH [1] for allnetwork service delivery to the subscriber. In the DES administrativemodel, each subscriber is associated with one more EDGE SWITCHES [1]that are installed at the subscriber premise for the purpose of networkservice delivery. A residence or single-location business entity may beviewed as a single subscriber, or in the case of a business withmultiple locations (i.e. branch offices), a collection of subscribers.

[0353] Each subscriber enables a set of Class of Service “capabilities”(i.e. the subscriber purchases “capabilities” in the form of networkservices) that describes the collection of features, functions, andservices that they would like to be able to access. These capabilitieswill determine which network services their particular EDGE SWITCH [1]will be capable of delivering.

[0354] The subscriber may then activate or deactivate selected Class ofService capabilities at their discretion. The collection of Class ofService capabilities that the subscriber has activated or deactivated iscalled their Class of Service “settings.” A subscriber cannot activateany capability not previously enabled. The EDGE SWITCH [1] will notrender any enabled capability that is not shown in the settings to beactivated.

[0355] Once activated, a setting may require additional information fromthe subscriber in order for the corresponding feature, function, orservice to operate correctly. For those settings, the subscriberconfigures “preferences” that further describe details as to exactly howthe Class of Service settings should be interpreted. Preferences usuallytake the form of parameters that must be selected or typed in by thesubscriber through a configuration application (e.g. telephone numbers,screen names, service options).

[0356] EDGE SWITCH [1] service delivery requires that subscriber Classof Service capabilities, settings, and preferences are stored locally inthe FILE SYSTEM [1.23.4], each in the form of a machine-readable dataobject called a “service profile.” Service profiles may be created tostore subscriber-specific information required by a variety ofapplications. CALL PROCESSING APPLICATIONS [1.23.2] require serviceprofiles as a means to store subscriber-specific parameters that effecttheir control flow. In some cases, service profiles may be created onthe EDGE SWITCH [1] by certain network-based applications to function as“cookies,” storing application-specific information required for servicedelivery.

CONFIGURATION PROFILES [1.23.5]

[0357] Database stored on FILE SYSTEM [1.23] that contains configurationinformation specific to a particular EDGE SWITCH [1] and used for itsbasic operation. In the DES administrative model, each subscriber isassociated with one or more EDGE SWITCH [1], each of which may have aunique set of physical and network-related configuration parameters notdirectly related to Class of Service.

[0358] Virtually every software component of the EDGE SWITCH [1]requires a CONFIGURATION PROFILE that includes initialization andrun-time parameters. As a few examples, CONFIGURATION PROFILES stored onthe EDGE SWITCH [1] may include the number of terminals that it may haveplugged into it, available bitrate of its connection to the BROADBANDACCESS NETWORK [6.1], input/output buffer sizes, QoS parameters, IProuting parameters, IP address assignments, and function key layoutprofiles for TELEPHONE STATIONS [3].

EDGE SWITCH BASIC FEATURES [1.24]

[0359] The term EDGE SWITCH BASIC FEATURES refers to a specificcollection of end-user features and functions that: (a) have becomewell-established in common use; (b) are likely to be highly-utilized ona day-to-day basis by the target subscriber group; and (c) are unlikelyto change over time. The vast majority of voice, video, and datacommunications functions fall into this category, with features thatinclude Customer Local Access Signaling Services (A.K.A. “CLASSfeatures”), Centrex features, office telephone features, basic videochannel selection, data firewall features, and Virtual Private (data)Networking, to name a few. EDGE SWITCH BASIC FEATURES are sorted intothree broad categories according to the terminal type used to presentthem to the subscriber:

[0360] TELEPHONE STATION FEATURES

[0361] SET-TOP BOX FEATURES

[0362] COMPUTER WORKSTATION FEATURES

[0363] These feature categories define the core feature set of the EDGESWITCH [1]. Network services are built up by enabling collections ofthese basic features, and adding to them access to network-basedfeatures and services. A network-based feature may be used in some casesto override a basic feature for the purpose of providing enhanced oralternative functionality that is logically equivalent to the basicfeature. The three categories of basic features are discussed below indetail:

TELEPHONE STATION FEATURES

[0364] For the purposes of this disclosure, the respective types ofTELEPHONE STATION FEATURES will be differentiated on the basis ofwhether they generally enhance usability in a wide variety of subscriberenvironments, or whether the are primarily applicable to an officeenvironment. The following list summarizes common features that“generally enhance usability in a wide variety of subscriberenvironments:”

[0365] Basic dial-tone

[0366] Automatic callback

[0367] Last number redial

[0368] Repeat dialing

[0369] Audible message-waiting indication (stutter dial tone)

[0370] Visible message-waiting indication (indicator lamp)

[0371] Distinctive ringing

[0372] Call-waiting indication/call-waiting cancel

[0373] Caller-ID with name

[0374] Call-blocking

[0375] Call-forwarding

[0376] Direct-connect

[0377] Emergency 911

[0378] The EDGE SWITCH [1] supports basic dial-tone, enabling thesubscriber to originate (or receive) both on-network calls andoff-network calls. Call-blocking features (A.K.A. “call-divertingfeatures”) enable the EDGE SWITCH [1] to block the origination of a call(outbound voice call) by a particular TELEPHONE STATION [3] based on thecalled party dialing number, or to block answering of a call (inboundvoice calls) by a particular TELEPHONE STATION [3] based on the callingparty dialing number. The EDGE SWITCH [1] supports configurable callblocking of this type, wherein the subscriber may selectively blockinbound and/or outbound calls by specifying area codes, exchanges, andline numbers (or various combinations of the three).

[0379] Call-forwarding features enable the EDGE SWITCH [1] toautomatically transfer (redirect) an inbound call based on a number ofconsiderations. Call-forwarding features are often activated toautomatically or conditionally transfers inbound calls to applicationservers for further processing or to provide access to NETWORK-BASEDENHANCED SERVICES [18]. Examples of NETWORK-BASED ENHANCED SERVICES [18]that may be accessed via call-forwarding include an auto attendant (usedto answer calls directed to a main office number), voice mail, automaticcall distribution, group conferencing bridge, or a personal callscreening service. The EDGE SWITCH [1] supports configurablecall-forwarding, wherein the subscriber may program it to redirectinbound calls based on:

[0380] Point of origination (determined by calling party dialingnumber);

[0381] Determination of a busy or “ring-no-answer” condition existingfor the called party dialing number;

[0382] Determination that the incoming call is a fax or modem call;

[0383] Date, day of week, or time of day.

[0384] Direct-connect features (A.K.A. “direct-connect originating”)enable the EDGE SWITCH [1] to automatically originate a call to apre-programmed dialing number when a TELEPHONE STATION [3] goesoff-hook, or upon the detection of some other event, such as aparticular TELEPHONE STATION [3] function key sequence. Direct-connectfeatures are often used for security telephones outside of a building,or at kiosks to provide immediate access to a call center help desk;they may also be used by the EDGE SWITCH [1] to implement speed-dialingby associating certain TELEPHONE STATION [3] key sequences withsubscriber-programmed speed-dialing numbers stored in LOCAL CALL ROUTINGTABLES [1.23.3].

[0385] Support for Emergency 911 (E911) is implemented by configuringthe dialing number “911” as a reserved dialing number. Any call to thedialing number 911 creates a connection to a SIP APPLICATION SERVER [13]or TDM APPLICATION SERVER [7.4] (through a PSTN GATEWAY [8]) thatsupports emergency services intervention. SIP network signaling passesthe calling party dialing number to the APPLICATION SERVER, which thenmay determine the physical (geographical) location of the calling partyas would be required to support emergency services intervention.

[0386] Customer Local Access Signaling Services (A.K.A. “CLASS features)comprise an additional layer of features that make TELEPHONE STATIONS[3] more generally useful in both residential and office settings.Depending upon one's point of reference, there is a significant overlapbetween what some may consider “CLASS features” and “office telephonefeatures.” Many of the features mentioned above, such as DistinctiveRinging and Audible message-waiting indication are considered by mostlocal exchange carriers as CLASS features. For the purposes of thisdisclosure, CLASS features are not viewed as a distinct feature set andare instead subsumed by the broader category of TELEPHONE STATIONFEATURES.

[0387] Office telephone features (A.K.A. “Centrex” or “PBX features”)comprise an additional layer of specialized features that make TELEPHONESTATIONS [3] more useful in an office environment. Certain officetelephone features make it possible for a user at a TELEPHONE STATION[3] to transfer calls between TELEPHONE STATIONS [3] that may notnecessarily be plugged into the same EDGE SWITCH [1]. In the case whereTELEPHONE STATIONS [3] are not plugged into the same EDGE SWITCH [1],implementation of certain features may require special communicationbetween EDGE SWITCHES [1] in which a SIP call session is initiated fromone to another, not to set-up a new call, but to request that a call inprogress be managed in a particular way (e.g. transferred to a differentSIP signaling endpoint residing on a different EDGE SWITCH [1]). Thefollowing list summarizes common office telephone features that are“primarily applicable to an office environment:”

[0388] Private telephone network (private dialing plan)

[0389] Speed dialing

[0390] Multiple line appearances

[0391] Three-way calling

[0392] Call-hold

[0393] Call-transfer

[0394] Call-pickup

[0395] Call-park

[0396] Call-waiting with display

[0397] Call log

[0398] Calling reason display

[0399] Do not disturb

[0400] Executive busy override

[0401] Feature button support

[0402] Make busy key

[0403] The DES as a system supports the ability to create a virtuallyunlimited number of private telephone networks (A.K.A. “virtual privatetelephone network” or “virtual telephone network”) that are implementedby programming private dialing plans into participating EDGE SWITCHES[1]. Generally speaking, a private telephone network is a collection oftelephone endpoints that may address each other as specific community ofusers, thus enabling the carrier to offer special configuration optionsand rate plans to participating subscribers. Often, on-network callsmade between participating subscribers are billed at a flat rate. Theprivate dialing plan is managed by the subscriber and supportsabbreviated dialing number formats that seamlessly integrate withexisting dialing plans (e.g. the North American Dialing Plan).

[0404] Private telephone networks may operate within a single IP CARRIERNETWORK [6] or within a wider area through a more expansive IP networkinfrastructure that consists of interconnected IP CARRIER NETWORKS [6].Since EDGE SWITCH [1] support for private telephone networks is based ondialing numbers, a private telephone network can include both SIPnetwork signaling endpoints within the IP CARRIER NEWORKS [6] and PSTN[7] endpoints accessible through a PSTN GATEWAY [8].

SET-TOP BOX FEATURES

[0405] SET-TOP BOXES [4] are known to the EDGE SWITCH [1] as stand-aloneSIP network signaling endpoints. The EDGE SWITCH [1] assumes that theywill originate and answer multimedia call sessions independently andwill support only limited remote (indirect) control of their featuresets by CALL PROCESSING APPLICATIONS [1.23.2] running on the EDGE SWITCH[1]. SET-TOP BOXES [4] originate multimedia call sessions to SIPAPPLICATION SERVERS [13] that are capable of delivering streaming videocontent to the connecting SET-TOP BOX [4].

[0406] In support of this type of video (multimedia) call session, theSIP PROTOCOL STACK [1.15] residing on the EDGE SWITCH [1] functions as aSIP Proxy Server, mediating the multimedia call session. the CALLPROCESSING APPLICATION [1.23.2] managing the multimedia call session mayat the same time communicate with the SET-TOP BOX [5] over the IPconnection to the access its internal feature set. The following listsummarizes common SET-TOP BOX [5] features that should be implemented asEDGE SWITCH BASIC FEATURES:

[0407] Detect, decode, and translate multimedia channel selectionprotocol

[0408] Detect, decode, and translate interactive services protocols(e.g. pay-per-view)

[0409] Display text overlay on top of video image

[0410] Control audio output gain

[0411] Detect, decode, and translate camera control protocol fortwo-multimedia applications

[0412] Download/upload device settings and preferences

COMPUTER WORKSTATION FEATURES

[0413] These features relate to the EDGE SWITCH'S [1] ability to providedata connectivity through the COMPUTER DATA INTERFACE [1.4]. Datafeature examples include:

[0414] Network Address Translation (NAT) to provide IP address supportfor multiple COMPUTER WORKSTATIONS [5];

[0415] Programmable firewall features used to support file systemprotection and content filtering;

[0416] Dynamic Host Configuration Protocol (DHCP);

[0417] Virtual Private (data) Networking (VPN);

[0418] Packet metering for connects that use QoS transport services;

[0419] Admission control, dialing number assignment, and protocolmessage grooming for SIP call sessions.

EDGE SWITCH OVERRIDE FEATURES [1.25]

[0420] The term EDGE SWITCH OVERRIDE FEATURES refers to a specificcollection of end-user features and functions that provide alternativeversions of EDGE SWITCH BASIC FEATURES [1.24]; they in some way modifyor enhance the behavior of EDGE SWITCH BASIC FEATURES [1.24], and may beimplemented internally by the EDGE SWITCH [1] as alternative versionsCALL PROCESSING APPLICATIONS [1.23.2] used to implement EDGE SWITCHBASIC FEATURES [1.24]. They may also be implemented external to the EDGESWITCH [1] as NETWORK-BASED OVERRIDE FEATURES [19] that aretransparently and dynamically accessed through the BROADBAND ACCESSNETWORK [6.1] when the feature is invoked. EDGE SWITCH OVERRIDE FEATURESimplemented externally as NETWORK-BASED OVERRIDE FEATURES [19] areaccessed by originating a SIP call session to a SIP APPLICATION SERVER[13].

SYSTEM MANAGEMENT PLATFORM [2]

[0421] All EDGE SWITCHES [1] are provisioned, configured, managed, andactively monitored by a SYSTEM MANAGEMENT PLATFORM deployed in a carriercentral office, or central office equivalent. The SYSTEM MANAGEMENTPLATFORM is a scalable, fault-tolerant, high-availability networkelement that functions as the nexus between carrier operations supportsystems (A.K.A. “carrier OSS” or “back-office interfaces”) and the EDGESWITCHES [1] deployed at the subscriber premise; it does not directlyparticipate in network service delivery at any time, but provides only asupporting, administrative role.

[0422] EDGE SWITCHES [1] do not interface the carrier OSS directly, butdo so only through mediation by software applications running on theSYSTEM MANAGEMENT PLATFORM. The software applications running on theSYSTEM MANAGEMENT PLATFORM support the following DES system managementfunctions:

[0423] Configure and upload software loads to the EDGE SWITCHES [1] aspart of a provisioning or upgrade process;

[0424] Dynamically provision EDGE SWITCH [1] service capabilities (usingdefault settings and preferences) according to a Class of Serviceprovisioning model;

[0425] Actively monitor EDGE SWITCH [1] service delivery and reportstatus through carrier OSS;

[0426] Remotely retrieve, view, and modify EDGE SWITCH [1] baseconfiguration and subscriber Class of Service parameters through carrierOSS;

[0427] Remotely initiate EDGE SWITCH [1] diagnostics and system testprocedures, and provide capability to report results through carrierOSS;

[0428] Synchronize EDGE SWITCH [1] information with same informationstored in SYSTEM MANAGEMENT PLATFORM databases and informationrespositories, including Class of Service capabilities, Class of Servicesettings, subscriber preferences, local call routing tables, subscriberservice profiles, and configuration profiles;

[0429] Collect event logs from EDGE SWITCHES [1], then store indatabases and information respositories according to programmedpolicies;

[0430] Sort and re-format billable events, then forward to carrier OSS;

[0431] Provide for and adapt to all standardized carrier OSSrequirements related to telecommunications service delivery (operations,administration, management and provisioning).

[0432] The software applications supporting these DES system managementfunctions operate in conjunction with scalable databases and informationrepositories (for bulk storage) that are integral components within theSYSTEM MANAGEMENT PLATFORM. In some cases, SYSTEM MANAGEMENT PLATFORMdatabases store and manage information that duplicates specific subsetsof information stored on the carrier's POLICY SERVER [14]. As a result,operations support system workflow models provide for some level ofsynchronization to ensure consistency between the DES and the carrierOSS.

[0433] SYSTEM MANAGEMENT PLATFORM databases and informationrespositories provide reliable, redundant storage for the following:

[0434] Administrative information needed to track and manage EDGE SWITCH[1] deployments at the subscriber premise, including a subscriberdatabase that details the physical addresses, hardware revisions,software revisions, and physical locations of all EDGE SWITCHES [1]assigned to each subscriber;

[0435] Synchronized backup copy of all subscriber-specific informationstored on every EDGE SWITCH [1], including Class of Servicecapabilities, Class of Service settings, subscriber preferences, localcall routing tables, subscriber service profiles, and EDGE SWITCH [1]configuration profiles;

[0436] Software loads, event logs, service records, billing records,provisioning templates, diagnostic reports, and other operationalinformation referenced by administrative information or received asoutput from the EDGE SWITCHES [1] in the course of network servicedelivery.

TELEPHONE STATION [3]

[0437] Terminal device that is plugged into the TELEPHONE LINE INTERFACE[1.9] and used for voice communications. The term “voice communications”refers to the ability of a terminal device to participate directly orindirectly as an endpoint in a “voice call session.” A voice callsession is defined as a SIP call session in which at least one bearerconnection is transporting voice media content. A TELEPHONE STATION doesnot support SIP network signaling and cannot present itself to the IPCARRIER NETWORK [6] as a SIP network signaling endpoint; therefore itcannot participate directly in a voice call session and relies upon theEDGE SWITCH [1] to perform the necessary conversions.

[0438] A TELEPHONE STATION communicates with the EDGE SWITCH [1]directly through the TELEPHONE LINE INTERFACE [1.9] using analogelectrical (or potentially digital) device-level telephone signaling(i.e. not network signaling). Beyond support for basic telephone linesignaling (e.g. on-hook, off-hook, DTMF tone generation), device-leveltelephone signaling is used by the TELEPHONE LINE INTERFACE [1.9] toactivate and control special features supported by the TELEPHONESTATION, such as illuminating message-waiting indication lamps or todetect feature key presses by the user. Ultimately, it becomes the taskof the EDGE SWITCH [1] (through the TELEPHONE LINE INTERFACE [1.9] andother internal components) to convert the TELEPHONE STATION'S analog ordigital device-level telephone signaling and voice transmissionconventions to and from IP packets containing SIP network signalinginformation and digitally-encoded voice, respectively.

[0439] TELEPHONE STATIONS [3] work best with EDGE SWITCH [1] featureswhen they support function keys that the EDGE SWITCH [1] can convert toan appropriate user interface convention. EDGE SWITCH [1] CALLPROCESSING APPLICATIONS [1.23.2] and NETWORK-BASED ENHANCED SERVICES[18] are implemented with the highest possible degree ofdevice-independence, and therefore rely upon user input (feature keypresses) that comply to a known user interface convention.

[0440] A POTS telephone with programmable speed-dial keys or a PBXtelephone with dedicated functions keys can both be used as TELEPHONESTATIONS [3]. In the case of supporting a POTS telephone, the TELEPHONELINE INTERFACE [1.9] must embody “SLIC” (Subscriber Line InterfaceCircuit) functionality whereas in the case of supporting a digital PBXtelephone, the TELEPHONE LINE INTERFACE [1.9] must support a particular,vendor-specific line-level interface for that device.

SET-TOP BOX [4]

[0441] Terminal device that is plugged into the VIDEO STREAMING DEVICEINTERFACE [1.5] and used for multimedia communications. The term“multimedia communications” refers to the ability of a terminal deviceto participate directly or indirectly as an endpoint in a “multimediacall session.” A multimedia call session is defined as a SIP callsession in which at least one bearer connection is transporting videomedia content. In this disclosure, the term “video call session” shouldbe understood as synonymous with “multimedia call session.” The use ofthe term “video” remains to preserve the general concept of the EDGESWITCH [1] providing support for all three media types: voice, video,and data.

[0442] Depending on terminal device capabilities and networkcapabilities, a single multimedia call session may encapsulate anynumber of concurrent voice, video, and data bearer connectionssimultaneously, and any one of them may be operating in a half-duplex orfull-duplex mode. By plugging and ETHERNET SWITCH [20] into the VIDEOSTREAMING DEVICE INTERFACE [1.5], more than one SET-TOP BOX can beconnected to the EDGE SWITCH [1].

[0443] To participate in multimedia call sessions, the SET-TOP BOXinterfaces with a television set, using it as an audiovisual outputdevice. A camera apparatus may be connected to and controlled by theSET-TOP BOX for two-way multimedia communications. As required fordirect participation in a multimedia call session, the SET-TOP BOXsupports SIP network signaling and presents itself to the IP CARRIERNETWORK [6] as a SIP network signaling endpoint. It communicates withthe EDGE SWITCH [1] through the VIDEO STREAMING DEVICE INTERFACE [1.5]using: (a) a QoS IP connection; (b) SIP network signaling; and (c) anumber of adjunct, vendor-specific device control protocols as requiredto implement EDGE SWITCH BASIC FEATURES [1.24] described for the SET-TOPBOX.

[0444] Since the EDGE SWITCH [1] is functioning as a SIP Proxy Server,mediating the multimedia call session originated by the SET-TOP BOX, itmay directly communicate with the SET-TOP BOX over the same IPconnection for the purpose of accessing its internal feature sets.Vendor-specific device control protocols may be implemented either asdistinct protocols or as SIP extensions, depending on SET-TOP BOXrequirements.

[0445] A telephone terminal that supports SIP network signaling and thatcan present itself to the IP CARRIER NETWORK [6] as a SIP networksignaling endpoint is considered to be operationally identical to aSET-TOP BOX. A so-called “SIP phone” is an example of this type ofterminal device. Accordingly, a SIP phone could be plugged into theVIDEO STREAMING DEVICE INTERFACE [1.5] and participate directly in avoice call session.

[0446] Whereas a SIP phone cannot be controlled directly by theTELEPHONE LINE INTERFACE [1.9] using device-level telephone signaling,access to its internal feature set must be accomplished by communicatingwith it through the IP connection to it, using SIP extensions andpotentially other vendor-specific device control protocols as requiredto implement EDGE SWITCH BASIC FEATURES [1.24] described for theTELEPHONE STATION [3].

[0447] This disclosure has deliberately characterized SIP phones to bethe functional equivalent of SET-TOP BOXES to avoid creating confusionbetween the direct control of telephone features through the TELEPHONELINE INTERFACE [1.9] and the indirect control of telephone featuresthrough vendor-specific IP protocols.

COMPUTER WORKSTATION [5]

[0448] Terminal device that is plugged into the COMPUTER DATA INTERFACE[1.4] and used for data communications. In most cases, this terminaldevice will be a desktop PC with an Ethernet LAN adapter running an IPprotocol stack. By plugging an ETHERNET HUB [9] into the COMPUTER DATAINTERFACE [1.4], more than one COMPUTER WORKSTATION can be connected tothe EDGE SWITCH [1].

IP CARRIER NETWORK [6]

[0449] Large-scale, routed internet protocol (IP) network designed tosupport the delivery of voice, video, and data communications servicesto a subscriber base made up of potentially millions of subscribers. TheIP CARRIER NETWORK is a private network offering controlled access to apublic subscriber base. It is owned and operated by a telecommunicationscarrier (A.K.A. “facilities-based network service provider”). Itconsists of a backbone network that is used to interconnect a number ofaccess networks, and all transmission paths through both the backbonenetwork and the access network are engineered to ensure that bothsignaling and bearer channel connections can be maintained with aQuality of Service (QoS).

[0450] QoS generally refers to the ability of the network to honorcertain quality guarantees (i.e. minimum bit transfer rates, maximumallowable latentcy, maximum allowable jitter, maximum rate of packetloss, etc.) as necessary to support real-time, full-duplex voice andvideo calls in addition to providing “best effort” data communicationsat specified minimum bitrates.

[0451] An IP CARRIER NETWORK is fully managed such that its performance(QoS transmission and service delivery) is monitored at all times. Inaddition, such a network supports the capability to be securelypartitioned so as to logically or physically segregate subscriber data,and subscriber data types, from each other into Virtual Private (data)Networks. The IP CARRIER NETWORK in most cases is implemented as ahybrid network in that IP connectivity in the network layer (OSI Layer3) may be transported over an ATM packet-switched infrastructure in thedata link layer (OSI Layer 2).

BROADBAND ACCESS NETWORK [6.1]

[0452] Specific type of access network that is designed to provide arelatively high-bitrate IP data path to the subscriber premise. For thepurposes of this disclosure, the term “high-bitrate” is used looselyhere to characterize a minimum bit transfer rate of 128 Kbit/second forboth the downstream (toward the premise) or upstream (away from thepremise) direction. For most implementations without video support, itis recommended that BROADBAND ACCESS NETWORK support a nominal bittransfer rate of at least 500 kilobit/second for both the downstream orupstream direction. Support for video services would require a 20megabit/second downstream bitrate capacity.

[0453] In addition to minimum bitrate requirements, the BROADBAND ACCESSNETWORK must support QoS for its connections. The BROADBAND ACCESSNETWORK is often described as the segment of the IP CARRIER NETWORK[6.1] that bridges the “last mile” between the central office and thesubscriber premise. Examples of “last mile” technologies that aresuitable for integration into the BROADBAND NETWORK INTERFACE [1.1]include Digital Subscriber Line (DSL), coaxial cable, T1 in unchannelledmode, and Passive Optical Network (PON).

DC POWER SOURCE [6.2]

[0454] The EDGE SWITCH [1] is a computing device that requires a DCPOWER SOURCE to operate. BROADBAND ACCESS NETWORKS [6.1] based on DSL orcoaxial cable usually provide power through the copper wire or cable,respectively. In some cases, this source is sufficient to power the EDGESWITCH [1]. Otherwise, power must be provided at the premise.

PSTN [7]

[0455] Public Switched Telephone Network. The network depicted in FIG. 1consisting of CENTRAL OFFICE SWITCHES and a TDM TRANSPORT NETWORK.

CENTRAL OFFICE SWITCH [7.1]

[0456] End-office switch deployed in a central office as the PSTN [7]network element used to provide telephone service to networksubscribers. It is the same as the CENTRAL OFFICE SWITCH depicted inFIG. 1. The telephone features provided by the CENTRAL OFFICE SWITCH arevirtually identical to the TELEPHONE STATION FEATURES described as asubset of the EDGE SWITCH BASIC FEATURES [1.24].

T1/E1/PRI [7.2]

[0457] T1, E1 or ISDN Primary Rate Interface digital trunk interfacesused in the PSTN [7]. T1, E1, and PRI are based upon circuit-switchedtime division multiplex (TDM) technology; they enable the transmissionof voice or bearer channel content along with varying degrees of networksignaling information.

SS#7 [7.3]

[0458] Signaling System #7; the out-band signaling network used in thePSTN [7].

TDM APPLICATION SERVER [7.4]

[0459] Application server deployed in a central office as a PSTN [7]network element used to provide NETWORK-BASED ENHANCED SERVICES [18] tonetwork subscribers. The TDM APPLICATION SERVER contains hardware andsoftware components required to support the operation of one or moreNETWORK-BASED ENHANCED SERVICES [18]. It typically presents access tothese services through a digital trunk interface (see T1/E1/PRI [7.2]).

[0460] The TDM APPLICATION SERVER operates conceptually as an array of“computer-controlled” telephones in which the service logic contained ina software application program replaces a human operator as thecontrolling entity. According to this model, the software applicationprogram is able to use a variety of system resources (databases, speechrecognition systems, media storage systems) to providecomputer-controlled, personalized network services to connecting voicetelephones.

PSTN GATEWAY [8]

[0461] ESN connectivity element that translates network signaling andbearer channel encoding formats so as to enable a call session in whichone end of the call is a SIP network signaling endpoint in the IPCARRIER NETWORK [6] and the other end is a legacy TDM endpoint in thePSTN [7].

ETHERNET HUB [9]

[0462] Simple, low-cost, multi-port data distribution device thatenables data communications to occur between all network devices pluggedinto it using Ethernet technology or the equivalent. This type of devicehas only modest transmission capacity and therefore cannot guaranteethat a certain minimal bandwidth is maintained for each data pathpassing through it. This device may operate in a wired or wirelesscapacity.

DNS SERVER [10]

[0463] Distributed database application (A.K.A. “Domain Naming Server”)that works at the transport layer (OSI Layer 4—above the network layer)to provide name-to-address mapping for all client applications in an IPnetwork. The client applications can include e-mail, web hosting, andSIP-based telecommunications. It is a component in the DES carrierreference network architecture and serves multiple purposes as it wouldin any IP-based network architecture.

[0464] Three principal DNS SERVER functions stand out as mostsignificant to the operation of the DES:

[0465] Translate generic network element names into one or more IPaddresses that correspond to actual physical instances of that networkelement type;

[0466] Convert E.164 dialing numbers into IP addresses as required forcall routing with the IP network;

[0467] Enable load balancing by providing IP addresses for multipleinstances of a certain type of network element or other networkresource.

WEB SERVER [11]

[0468] Software application program that implements support for the “webserver” functionality described by IETF RFC 2068 on Hypertext TransferProtocol—HTTP Version 1.1 (HTTP). The WEB SERVER is a component in theDES carrier reference network architecture and primarily used as a meansto enable subscribers to communicate indirectly with EDGE SWITCHES [1]for the purposes of interactive configuration and interactive networkservice delivery.

[0469] With respect to interactive configuration, the WEB SERVERpresents a web browser-based graphical user interface that enablessubscribers to selectively enable or disable Class of Service settingsand then to control or input preferences that relate to the delivery ofactivated network services. The WEB SERVER performs an authenticatedlog-in to the subscriber's EDGE SWITCH [1], and thus functions as anintermediary agent to ensure that the subscriber's settings andpreferences are written to the target EDGE SWITCH [1] in a secure andsyntactically correct manner.

[0470] To support interactive network service delivery to thesubscriber, the WEB SERVER once again functions as an intermediaryagent, hosting service-related applications that enable browser-basedinteractions between the subscriber and the EDGE SWITCH [1]. The WEBSERVER again performs an authenticated log-in to the subscriber's EDGESWITCH [1], but this time for the purposes of (a) accessing call logdata stored within it so that it may be used as application data, and(b) exerting control over internal EDGE SWITCH [1] features, such asoriginating or answering a call.

SIP PROXY SERVER [12]

[0471] This term refers specifically to a network-based implementationof a stand-alone SIP Proxy Server (or SIP Proxy Server cluster) and notto the SIP Proxy Server functionality supported by the SIP PROTOCOLSTACK [1.16]. While the SIP Proxy Server functionality supported by bothis essentially identical, they operate independently in support ofdifferent roles.

[0472] According to IETF RFC 2543 on SIP: Session Initiation Protocol aSIP PROXY SERVER is defined as follows:

[0473] “An intermediary program that acts as both a server and a clientfor the purpose of making requests on behalf of other clients. Requestsare serviced internally or by passing them on, possibly aftertranslation, to other servers. A proxy interprets, and, if necessary,rewrites a request message before forwarding it.”

[0474] The SIP PROXY SERVER is a component in the DES reference carriernetwork architecture and is required to support many SIP networksignaling operations within it by shuttling SIP messages back and forthbetween two or more SIP User Agents participating in a SIP call session.

[0475] Specifically, the SIP PROXY SERVER functions much like anintermediary SIP message router to ensure that the SIP network signalingmessages to/from the SIP endpoints in the network are ultimatelychanneled to the correct destination. In this message-routing capacity,several SIP PROXY SERVERS can cooperate to pass SIP network signalingmessages bi-directionally through a hierarchy of SIP PROXY SERVERS, eachof which gets it closer to the target endpoint. SIP PROXY SERVERS accessboth the DNS SERVER [10] and the POLICY SERVER [14] to determine how toroute SIP call sessions within the IP CARRIER NETWORK [6].

SIP APPLICATION SERVER [13]

[0476] ESN connectivity element deployed in an IP CARRIER NETWORK [6] toprovide NETWORK-BASED ENHANCED SERVICES [18] to network subscribers. TheSIP APPLICATION SERVER contains hardware and software componentsrequired for the operation of one or more NETWORK-BASED ENHANCEDSERVICES [18]. It presents itself as a SIP network signaling endpointthat may communicate with any other SIP network signaling endpoint in aSIP call session.

[0477] It is assumed that the SIP APPLICATION SERVER will provide ameans, directly or indirectly, to support one or more RTP bearer channelconnections that are likely to be required for voice or multimedia callsessions. Because bearer channel capabilities for these SIP-based callsessions are assumed, the SIP APPLICATION SERVER may viewed conceptuallyto operate as an array of “computer-controlled” voice or multimediaterminals in which the service logic contained in a software applicationprogram replaces a human operator as the controlling entity.

[0478] According to this model, the software application program is ableto use a variety of system resources (databases, speech recognitionsystems, media storage systems) to provide computer-controlled,personalized network services to connecting voice or multimediaterminals.

[0479] As a consequence of the fact that most call sessions in which theSIP APPLICATION SERVER participates are mediated through a SIP PROXYSERVER [12], each SIP signaling path created to support these callsessions may be used as a context to invoke additional capabilities ofthe SIP PROXY SERVER [12].

[0480] By exchanging SIP messages with the SIP PROXY SERVER [12](through the SIP signaling path created to support a call session), theapplication program responsible for controlling a call session mayperform complex call control operations, such as to transfer calls,add/drop call participants, or connect to a specialized type of SIPAPPLICATION SERVER [13] called a “media server” for the purpose ofinvoking media services. A media server is capable of supportingmedia-intensive application services such as speech recognition,interactive voice response, or music-on-hold. Media servers are called“dialog servers” when they interpret and execute interactive voiceresponse commands written in Voice XML.

POLICY SERVER [14]

[0481] Collection of database applications owned, operated, andmaintained by the carrier for the purpose of managing network servicedelivery to network subscribers. These database applications arereferred to collectively as a POLICY SERVER for two reasons:

[0482] (a) It is a practical impossibility to accurately characterize a“generic” carrier policy database server configuration; carrier networkelements of this type will vary according to their unique networkinfrastructure requirements;

[0483] (b) It is a practical impossibility to accurately characterizehow a particular carrier logically organizes its information; each mayconceive schema and/or combine data objects in very different ways thatwill vary according to their unique network infrastructure requirements;

[0484] The POLICY SERVER thus represents a logical entity that storesessential network operational support information and enable DES systemelements to access that information. Information stored on the POLICYSERVER includes:

[0485] Subscriber-specific information (Class of Service, accountstatus, service profiles, preferences);

[0486] Connection policies and related call routing information; dialingplans;

[0487] Billing policies and rate plans for service delivery; Generalnetwork authentication services for all human and machine users.

[0488] The connection policies are abstract data representations of thecontrol logic necessary to route calls, invoke services, and performother interconnection operations that define the behavior of the SIPPROXY SERVER [12] as it establishes specific call paths through the IPCARRIER NETWORK [6].

NETWORK PROVISIONING SYSTEM [15]

[0489] Network operations support system used by carrier to enable,disable, or modify network service delivery for network subscribers.

NETWORK OPERATIONS CENTER [16]

[0490] Network operations support system used by carrier to configure,monitor, troubleshoot, and manage network elements involved indelivering network services to network subscribers.

NETWORK BILLING SYSTEM [17]

[0491] Network operations support system used by carrier to collectbilling records from network elements involved in delivering networkservices to network subscribers, and then to convert them to customerinvoices based on billing policies and rate plans.

NETWORK-BASED ENHANCED SERVICES [18]

[0492] In contrast to NETWORK-BASED OVERRIDE FEATURES [19],NETWORK-BASED ENHANCED SERVICES are typically stand-alone networkservices that perform complete, independent functions; they are notfunctionally bound to any EDGE SWITCH [1] feature, but are generallyaccessible through the IP CARRIER NETWORK [6] using TELEPHONE STATIONS[3] and/or SET-TOP BOXES [4] plugged into and EDGE SWITCH [1]. They aregeneral-interest applications that appeal to a wide audience.

[0493] Examples of NETWORK-BASED ENHANCED SERVICES include voicecall-answering, group audio conferencing, language translation services,or video content delivery. Most NETWORK-BASED ENHANCED SERVICES aresuitable to be offered as either stand-alone applications or as part ofan overall services package that incorporates other features andservices. An important distinction between EDGE SWITCH BASIC FEATURES[1.24] and NETWORK-BASED ENHANCED SERVICES is that the latter are notsubstitutes for, or alternative versions of, EDGE SWITCH BASIC FEATURES[1.24], but are independent, companion network services with which EDGESWITCH BASIC FEATURES [1.24] must interoperate.

NETWORK-BASED OVERRIDE FEATURES [19]

[0494] Special-purpose, network-based applications that work inconjunction with EDGE SWITCH OVERRIDE FEATURES [1.25] for the purpose ofimparting the EDGE SWITCH [1] with more advanced feature deliverycapabilities. Advanced features of this type are likely to appeal toonly a select subset of subscribers and/or are potentially costly toimplement; thus they do not meet the requirements necessary to beimplemented as EDGE SWITCH BASIC FEATURES [1.24].

[0495] An simple example of a NETWORK-BASED OVERRIDE FEATURE is an“inbound call management” network-based application (implementing thefeature) that enables the end-user to accept or deny an incoming callfrom the PC desktop. In this case, the EDGE SWITCH [1] would transferthe inbound call to a network-based application rather than simplyringing the TELEPHONE STATION [1]. The network-based application wouldsupport a NETWORK-BASED OVERRIDE FEATURE that would present the identityof the calling party on the PC desktop (through a web browser graphicaluser interface). If the end-user accepts the incoming call through theweb browser graphical user interface, the NETWORK-BASED OVERRIDE FEATUREtransfers the call back to the EDGE SWITCH [1] with a marker indicatingthat call-setup should be allow to proceed in the normal fashion.

ETHERNET SWITCH [20]

[0496] Multi-port data distribution device based on Ethernet technology.The ETHERNET SWITCH enables data communications to occur between allnetwork devices plugged into it at the same time, and is able toguarantee a minimal amount of bandwidth for each data transmission pathpassing through it. This device may operate in a wired or wirelesscapacity.

SUBSCRIBER NETWORK INTERFACE (POTS) [22]

[0497] Demarcation point that defines the interface between the publiccarrier network (PSTN [7] or IP CARRIER NETWORK [6]) and thesubscriber's inside wiring plant. The SUBSCRIBER NETWORK INTERFACE(A.K.A. “Telco Entrance Facility”) is required to be physically locatedin a “publicly accessible place.” Its physical manifestation is usuallya modest wire interface device (channel bank) used to connect copperwires from the street to the copper wiring within the premise. From aregulatory perspective, everything on the network side of the SUBSCRIBERNETWORK INTERFACE is the responsibility of the carrier and everything onthe premise side is the responsibility of the subscriber. Forresidential telephone service, the SUBSCRIBER NETWORK INTERFACE isusually located on the outside of the residence. Businesses often havemore complex termination requirements and allocate a wiring closet toserve this purpose.

[0498] A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

What is claimed is:
 1. A network device comprising: a plurality ofcommunication interfaces, including a telephone line interface, acomputer data interface, and a broadband network interface; a processor;a machine-readable storage medium which during use stores a callprocessing application and service profiles, and which stores executableinstructions to mediate communications between the plurality ofcommunication interfaces, the instructions causing the network device todetect network signaling events or trigger points in a telephone calland invoke the call processing application in response to the detectednetwork signaling events or trigger points, the call processingapplication operating according to parameters defined in the serviceprofiles.
 2. The network device of claim 1, wherein the plurality ofcommunication interfaces further includes a video streaming deviceinterface.
 3. The network device of claim 1, wherein the broadbandnetwork interface terminates a broadband network link that joins acustomer premises to a packet carrier network.
 4. The network device ofclaim 1, wherein the instructions further cause the network device toroute IP data between the computer data interface and the broadbandnetwork interface.
 5. The network device of claim 1, wherein the networkdevice is contained in a single physical enclosure.
 6. The networkdevice of claim 1, wherein the instructions further cause the networkdevice to provide a first SIP proxy agent to represent a telephone thatuses the telephone line interface, and provide a second SIP proxy agentto represent a computer that uses the computer data interface.
 7. Thenetwork device of claim 1, wherein the storage medium during use furtherstores call routing tables, and the instructions further cause thenetwork device to perform call routing for telephone calls that use thetelephone line interface.
 8. The network device of claim 1, wherein thestorage medium during use further stores call routing tables, and theinstructions further cause the network device to perform call routingfor telephone calls according to the call routing tables, the telephonecalls using the telephone line interface.
 9. A network devicecomprising: a plurality of communication interfaces, including atelephone line interface, a computer data interface, and a broadbandnetwork interface; a processor; a machine-readable storage medium whichduring use stores call routing tables, and which stores executableinstructions to mediate communications between the plurality ofinterfaces, the instructions causing the network device to perform callrouting according to the call routing tables, the telephone calls usingthe telephone line interface.
 10. The network device of claim 9, whereincall routing includes peer-to-peer call signaling between customerpremises over a shared IP network.
 11. The network device of claim 10,wherein the call signaling is performed without requiring statefulelements of the shared IP network above the IP infrastructure.
 12. Thenetwork device of claim 10, wherein the broadband network interfaceterminates a link that joins the network device to the shared IPnetwork.
 13. The network device of claim 9, wherein call routingincludes call signaling to a PSTN endpoint via a PSTN gateway that isreachable over the broadband network interface.
 14. The network deviceof claim 9, wherein the network device is contained in a single physicalenclosure.
 15. The network device of claim 9, wherein the instructionsfurther cause the network device to route IP data between the computerdata interface and the broadband network interface.
 16. The networkdevice of claim 9, wherein the plurality of communication interfacesfurther includes a video streaming device interface.
 17. A networkdevice comprising: a plurality of communication interfaces, including atelephone line interface, a computer data interface, and a broadbandnetwork interface; a processor; and a machine-readable storage mediumwhich stores executable instructions to mediate communications betweenthe plurality of interfaces, the instructions causing the network deviceto log a telephone event record to a telephone event repository, theevent record describing a telephone call communication mediated by thenetwork device.
 18. The network device of claim 17, wherein thetelephone event repository is included in the network device.
 19. Thenetwork device of claim 17, wherein the telephone event repository isremote relative to the network device.
 20. The network device of claim17, wherein the network device is contained in a single physicalenclosure.
 21. The network device of claim 17, wherein the plurality ofcommunication interfaces further includes a video streaming deviceinterface.
 22. A network device comprising: a broadband networkinterface; a plurality of interfaces, including a telephone lineinterface and a computer data interface; a processor; and amachine-readable storage medium that stores processor-executableinstructions to provide proxy agents, the instructions causing thenetwork device to provide a telephone SIP proxy agent to represent anon-SIP telephone that uses the telephone line interface, and provide adistinct SIP proxy agent for each additional device that uses aninterface in the plurality of interfaces, and the instructions furthercausing the network device to implement a proxy server that mediates allSIP communications over the broadband network interface involving thenon-SIP telephone and the each additional devices.
 23. The networkdevice of claim 22, wherein the computer data interface passes IP data.24. The network device of claim 22, wherein the plurality of interfacesincludes a video streaming device interface.
 25. The network device ofclaim 22, wherein the network device is contained in a single physicalenclosure.
 26. A method for establishing a voice-over-packet networkarchitecture, the method comprising: locating a system managementplatform in a shared packet network, the system management platformcollecting call log data from a plurality of network devices; anddistributing the plurality of network devices that each include atelephone line interface, a computer data interface, a broadband networkinterface terminating a link from the shared packet network, aprocessor, and a machine-readable storage medium storingprocessor-executable instructions to control telephone calls, theinstructions causing each network device to route telephone calls in apeer-to-peer fashion over the shared packet network and to send call logdata to the system management platform.
 27. The method of claim 26,wherein for each device the broadband network interface terminates alink from the shared packet network.
 28. The method of claim 26, whereinthe routing of telephone calls includes SIP signaling.
 29. The method ofclaim 26, wherein the storage medium further stores processor-executableinstructions to act as an SIP proxy server for devices using thetelephone line interface and for devices using the computer datainterface.
 30. The method of claim 26, wherein the shared packet networkuses IP protocols.
 31. The method of claim 26, wherein the shared packetnetwork uses ATM protocols.
 32. The method of claim 26, wherein theplurality of network devices each further include a video streamingdevice interface